Publications of Warren S. Warren    :chronological  alphabetical  combined listing:

%% Papers Published   
@article{fds234354,
   Author = {Branca, RT and Zhang, L and Warren, WS and Auerbach, E and Khanna, A and Degan, S and Ugurbil, K and Maronpot, R},
   Title = {In Vivo Noninvasive Detection of Brown Adipose Tissue
             through Intermolecular Zero-Quantum MRI},
   Journal = {PloS one},
   Volume = {8},
   Number = {9},
   Pages = {e74206},
   Year = {2013},
   ISSN = {1932-6203},
   url = {http://dx.doi.org/10.1371/journal.pone.0074206},
   Abstract = {The recent discovery of active Brown Adipose Tissue (BAT) in
             adult humans has opened new avenues for obesity research and
             treatment, as reduced BAT activity seem to be implicated in
             human energy imbalance, diabetes, and hypertension. However,
             clinical applications are currently limited by the lack of
             non-invasive tools for measuring mass and function of this
             tissue in humans. Here we present a new magnetic resonance
             imaging method based on the normally invisible
             intermolecular multiple-quantum coherence 1H MR signal. This
             method, which doesn't require special hardware
             modifications, can be used to overcome partial volume
             effect, the major limitation of MR-based approaches that are
             currently being investigated for the detection of BAT in
             humans. With this method we can exploit the characteristic
             cellular structure of BAT to selectively image it, even when
             (as in humans) it is intimately mixed with other tissues. We
             demonstrate and validate this method in mice using PET scans
             and histology. We compare this methodology with conventional
             1H MR fat fraction methods. Finally, we investigate its
             feasibility for the detection of BAT in humans. © 2013
             Branca et al.},
   Doi = {10.1371/journal.pone.0074206},
   Key = {fds234354}
}

@article{fds234604,
   Author = {Bouchard, L-S and Wehrli, FW and Chin, C-L and Warren,
             WS},
   Title = {Structural anisotropy and internal magnetic fields in
             trabecular bone: Coupling solution and solid dipolar
             interactions},
   Journal = {Journal of Magnetic Resonance},
   Volume = {176},
   Number = {1},
   Pages = {27-36},
   Year = {2005},
   url = {http://dx.doi.org/10.1016/j.jmr.2005.05.012},
   Abstract = {We investigate the use of intermolecular multiple-quantum
             coherence to probe structural anisotropy in trabecular bone.
             Despite the low volume fraction of bone, the bone-water
             interface produces internal magnetic field gradients which
             modulate the dipolar field, depending on sample orientation,
             choice of dipolar correlation length, correlation gradient
             direction, and evolution time. For this system, the probing
             of internal magnetic field gradients in the liquid phase
             permits indirect measurements of the solid phase dipolar
             field. Our results suggest that measurements of
             volume-averaged signal intensity as a function of gradient
             strength and three orthogonal directions could be used to
             non-invasively measure the orientation of structures inside
             a sample or their degree of anisotropy. The system is
             modeled as having two phases, solid and liquid (bone and
             water), which differ in their magnetization density and
             magnetic susceptibility. A simple calculation using a priori
             knowledge of the material geometry and distribution of
             internal magnetic fields verifies the experimental
             measurements as a function of gradient strength, direction,
             and sample orientation. © 2005 Elsevier Inc. All rights
             reserved.},
   Doi = {10.1016/j.jmr.2005.05.012},
   Key = {fds234604}
}

@article{fds234602,
   Author = {Tian, P and Warren, WS},
   Title = {Ultrafast measurement of two-photon absorption by loss
             modulation},
   Journal = {Optics Letters},
   Volume = {27},
   Number = {18},
   Pages = {1634-1636},
   Year = {2002},
   ISSN = {0146-9592},
   Abstract = {We demonstrate a direct and sensitive technique for
             measuring two-photon absorption (TPA). An
             intensity-modulated femtosecond laser beam passes through a
             sample exhibiting TPA. A TPA signal at twice the modulation
             frequency is then generated and subsequently measured by a
             lock-in amplifier. The absolute TPA cross section of
             Rhodamine 6G at 800 nm is found to be (15.3 ± 2.0) × 10-50
             cm4 s/photon and agrees well with previously published
             results obtained with much higher intensity [J. Chem. Phys.
             112, 9201 (2000)]. Our method may be especially useful in
             measuring nonlinear absorptions of nonfluorescent materials.
             © 2002 Optical Society of America.},
   Key = {fds234602}
}

@article{fds234598,
   Author = {Warren, WS and Ahn, S and Mescher, M and Garwood, M and Ugurbil, K and Richter, W and Rizi, RR and Hopkins, J and Leigh,
             JS},
   Title = {MR imaging contrast enhancement based on intermolecular zero
             quantum coherences},
   Journal = {Science},
   Volume = {281},
   Number = {5374},
   Pages = {247-251},
   Year = {1998},
   ISSN = {0036-8075},
   url = {http://dx.doi.org/10.1126/science.281.5374.247},
   Abstract = {A new method for magnetic resonance imaging (MRI) based on
             the detection of relatively strong signal from
             intermolecular zero-quantum coherences (iZQCs) is reported.
             Such a signal would not be observable in the conventional
             framework of magnetic resonance; it originates in long-range
             dipolar couplings (10 micrometers to 1 millimeter) that are
             traditionally ignored. Unlike conventional MRI, where image
             contrast is based on variations in spin density and
             relaxation times (often with injected contrast agents),
             contrast with iZQC images comes from variations in the
             susceptibility over a distance dictated by gradient
             strength. Phantom and in vivo (rat brain) data confirm that
             iZQC images give contrast enhancement. This contrast might
             be useful in the detection of small tumors, in that
             susceptibility correlates with oxygen concentration and in
             functional MRI.},
   Doi = {10.1126/science.281.5374.247},
   Key = {fds234598}
}


%% Papers Accepted   
@article{fds234347,
   Author = {Villafana, TE and Brown, WP and Delaney, JK and Palmer, M and Warren,
             WS and Fischer, MC},
   Title = {Femtosecond pump-probe microscopy generates virtual
             cross-sections in historic artwork.},
   Journal = {Proceedings of the National Academy of Sciences of
             USA},
   Volume = {111},
   Number = {5},
   Pages = {1708-1713},
   Year = {2014},
   Month = {February},
   ISSN = {0027-8424},
   url = {http://dx.doi.org/10.1073/pnas.1317230111},
   Abstract = {The layering structure of a painting contains a wealth of
             information about the artist's choice of materials and
             working methods, but currently, no 3D noninvasive method
             exists to replace the taking of small paint samples in the
             study of the stratigraphy. Here, we adapt femtosecond
             pump-probe imaging, previously shown in tissue, to the case
             of the color palette in paintings, where chromophores have
             much greater variety. We show that combining the contrasts
             of multispectral and multidelay pump-probe spectroscopy
             permits nondestructive 3D imaging of paintings with
             molecular and structural contrast, even for pigments with
             linear absorption spectra that are broad and relatively
             featureless. We show virtual cross-sectioning capabilities
             in mockup paintings, with pigment separation and
             nondestructive imaging on an intact 14th century painting
             (The crucifixion by Puccio Capanna). Our approach makes it
             possible to extract microscopic information for a broad
             range of applications to cultural heritage.},
   Doi = {10.1073/pnas.1317230111},
   Key = {fds234347}
}

@article{fds222757,
   Author = {T. Theis and Y. Feng and T.-L. Wu and W.S. Warren},
   Title = {Spin lock composite shaped pulses for efficient and robust
             pumping of dark states in magnetic resonance},
   Journal = {J. Chem. Phys},
   Year = {2013},
   Key = {fds222757}
}

@article{fds222760,
   Author = {K. Claytor and T. Theis and Y. Feng and W. S.
             Warren},
   Title = {Measuring Long-Lived 13C-Singlet State Lifetimes at Natural
             Abundance},
   Journal = {J. Magn. Reson},
   Year = {2013},
   Key = {fds222760}
}

@article{fds40790,
   Author = {B. Chance and S. Nioka and W.S. Warren and G. Yurtsever},
   Title = {"Mitochondrial NADH as the Bellwether of Tissue O2
             Delivery"},
   Booktitle = {Adv. Biol. (ISOTT)},
   Publisher = {Plenum Press, NY},
   Year = {2005},
   Key = {fds40790}
}

@article{fds234460,
   Author = {Bouchard, L-S and Warren, WS},
   Title = {Multiple-quantum vector field imaging by magnetic
             resonance},
   Journal = {J. Magn. Reson.},
   Volume = {176},
   Pages = {xx},
   Year = {2005},
   Key = {fds234460}
}

@article{fds234613,
   Author = {Bouchard, L-S and Warren, WS},
   Title = {Tensorial character of magnetization diffusion in periodic
             lattices},
   Journal = {Physical Review B - Condensed Matter and Materials
             Physics},
   Volume = {70},
   Number = {22},
   Pages = {224426-1-224426-9},
   Year = {2004},
   url = {http://dx.doi.org/10.1103/PhysRevB.70.224426},
   Abstract = {Averaged Bloch equations for magnetization evolution in a
             biphasic heterogeneous material with periodic structures are
             derived using a two-scale asymptotic expansion. Upscaling of
             the partial differential equations with microscopic boundary
             conditions results in equations of motion for the
             magnetization vector that are functionally similar to the
             Bloch equations, but without microscopic boundaries, and
             with a tensorial term describing effective diffusion
             behavior. In the process we obtain a prescription for
             calculating individual components of the diffusion tensor by
             solving an auxiliary boundary-valued problem on the
             microscopic unit cell. This allows, in particular, numerical
             calculations of the diffusion tensor for arbitrary
             geometries of the unit cellin a reasonable computing
             time.},
   Doi = {10.1103/PhysRevB.70.224426},
   Key = {fds234613}
}


%% Papers Submitted   
@article{fds234603,
   Author = {Lisitza, N and Song, Y-Q and Warren, WS},
   Title = {"Exploring permeation in blookd by its internal magnetic
             field"},
   Journal = {Proc. Natl. Acad. Sci.},
   Year = {2005},
   Key = {fds234603}
}

@article{fds234612,
   Author = {Bouchard, L-S and Chin, C-L and Wehrli, FW and Warren,
             WS},
   Title = {"Probing structural anisotropy in heterogeneous media via
             indirect measurements of the dipole-dipole interaction
             between solid and liquid phases"},
   Journal = {Phys. Rev. B.},
   Year = {2005},
   Key = {fds234612}
}

@article{fds234614,
   Author = {Miller, A and Fischer, M and Warren, WS},
   Title = {"Simultaneous measurement of two-photon absorption and
             self-phase modulation by femtosecond pulse
             shaping"},
   Journal = {Optics Letters},
   Year = {2005},
   Key = {fds234614}
}


%% Preprints   
@article{fds328168,
   Author = {Warren, WS and Robles, F and Fischer, M and Wilson, J and Deb, S and Ju, K and Degan, S and Warren, WS and Robles, F and Fischer, M and Wilson, J and Deb,
             S and Ju, K and Degan, S},
   Title = {Melanin-targeted nonlinear microscopy for label-free
             molecular diagnosis and stagingMelanin-targeted nonlinear
             microscopy for label-free molecular diagnosis and
             staging},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2016},
   Month = {April},
   ISBN = {9781943580101},
   url = {http://dx.doi.org/10.1364/TRANSLATIONAL.2016.TTh3B.3},
   Abstract = {© OSA 2016. Nonlinear pump-probe microscopy differentiates
             cutaneous, vulvar and conjunctival melanomas from less
             dangerous lesions, and can be used to assess metastatic
             potential. Applications in vivo (knockout mouse models) and
             in human biopsy are presented.},
   Doi = {10.1364/TRANSLATIONAL.2016.TTh3B.3},
   Key = {fds328168}
}

@article{fds328171,
   Author = {Wilson, JW and Warren, WS and Fischer, MC},
   Title = {Real-time digital signal processing in multiphoton and
             time-resolved microscopy},
   Journal = {Proceedings of SPIE},
   Volume = {9703},
   Year = {2016},
   Month = {January},
   ISBN = {9781628419375},
   url = {http://dx.doi.org/10.1117/12.2218102},
   Abstract = {© 2016 SPIE. The use of multiphoton interactions in
             biological tissue for imaging contrast requires highly
             sensitive optical measurements. These often involve signal
             processing and filtering steps between the photodetector and
             the data acquisition device, such as photon counting and
             lock-in amplification. These steps can be implemented as
             real-time digital signal processing (DSP) elements on
             field-programmable gate array (FPGA) devices, an approach
             that affords much greater flexibility than commercial photon
             counting or lock-in devices. We will present progress toward
             developing two new FPGA-based DSP devices for multiphoton
             and time-resolved microscopy applications. The first is a
             high-speed multiharmonic lock-in amplifier for transient
             absorption microscopy, which is being developed for
             real-time analysis of the intensity-dependence of melanin,
             with applications in vivo and ex vivo (noninvasive
             histopathology of melanoma and pigmented lesions). The
             second device is a kHz lock-in amplifier running on a low
             cost ($50 - $200) development platform. It is our hope that
             these FPGA-based DSP devices will enable new, high-speed,
             low-cost applications in multiphoton and time-resolved
             microscopy.},
   Doi = {10.1117/12.2218102},
   Key = {fds328171}
}

@article{fds328173,
   Author = {Robles, FE and Fischer, MC and Warren, WS},
   Title = {Dispersion-based stimulated Raman scattering spectroscopy,
             holography, and optical coherence tomography (Conference
             Presentation)},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {9712},
   Year = {2016},
   url = {http://dx.doi.org/10.1117/12.2212875},
   Doi = {10.1117/12.2212875},
   Key = {fds328173}
}

@article{fds328385,
   Author = {Robles, FE and Selim, MA and Warren, WS},
   Title = {Diagnosis and staging of female genital tract melanocytic
             lesions using pump-probe microscopy (Conference
             Presentation)},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {9689},
   Year = {2016},
   url = {http://dx.doi.org/10.1117/12.2212949},
   Doi = {10.1117/12.2212949},
   Key = {fds328385}
}

@article{fds234283,
   Author = {Wilson, JW and Degan, S and Gainey, CS and Deb, S and Dall, CP and Tameze-Rivas, Y and Zhang, J and Warren, WS},
   Title = {In vivo pump-probe microscopy of melanoma: Characterizing
             shifts in excited state photodynamics with respect to
             invasiveness},
   Journal = {Proceedings of SPIE},
   Volume = {9329},
   Year = {2015},
   Month = {January},
   ISBN = {9781628414196},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.2079886},
   Abstract = {© 2015 SPIE. Pump-probe microscopy is a multiphoton
             technique that generates molecular contrast from absorptive
             pigments, such as melanin. It holds the potential to be used
             as a non-invasive screening tool to discern whether a given
             early-stage melanoma has acquired the capacity for
             metastasis. Here, we examined lesions in a
             Braf(V600E)-driven model of melanoma to assess whether loss
             of the tumor suppressor gene Pten in a is accompanied by a
             shift in pigment expression, as measured in vivo by
             pump-probe microscopy. The data were analyzed to determine
             differences in the excited-state lifetime of melanins
             expressed in Pten-competent and Pten-loss pigmented lesions.
             Loss of the tumor suppressor Pten was found to be
             accompanied by a statistically significant decrease in
             pixel-average excited state lifetime (p =
             1.3e-4).},
   Doi = {10.1117/12.2079886},
   Key = {fds234283}
}

@article{fds328175,
   Author = {Villafana, TE and Brown, W and Warren, WS and Fischer,
             M},
   Title = {Ultrafast pump-probe dynamics of iron oxide based earth
             pigments for applications to ancient pottery
             manufacture},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {9527},
   Year = {2015},
   Month = {January},
   ISBN = {9781628416879},
   url = {http://dx.doi.org/10.1117/12.2184758},
   Abstract = {© 2015 SPIE. We demonstrate that ultrafast pump-probe
             microscopy provides unique dynamics for natural iron oxide
             and iron hydroxide earth pigments, despite their chemical
             similarity. First, we conducted a pump-probe spectroscopy
             study on heat-treated hematite (the pure red iron oxide
             mineral) and found the pump-probe dynamics to be temperature
             dependent. Second, we investigated pottery fired under known
             conditions and observed firing dependent pump-probe
             dynamics. Finally, we imaged a New World potshard from the
             North Carolina Museum of Art. Our results indicate that
             pump-probe microscopy could be a useful tool in elucidating
             pottery manufacture.},
   Doi = {10.1117/12.2184758},
   Key = {fds328175}
}

@article{fds328177,
   Author = {Wilson, JW and Anderson, M and Park, JK and Fischer, MC and Warren,
             WS},
   Title = {Separating higher-order nonlinearities in transient
             absorption microscopy},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {9584},
   Year = {2015},
   Month = {January},
   ISBN = {9781628417500},
   url = {http://dx.doi.org/10.1117/12.2187133},
   Abstract = {© 2015 SPIE. The transient absorption response of melanin
             is a promising optically-accessible biomarker for
             distinguishing malignant melanoma from benign pigmented
             lesions, as demonstrated by earlier experiments on thin
             sections from biopsied tissue. The technique has also been
             demonstrated in vivo, but the higher optical intensity
             required for detecting these signals from backscattered
             light introduces higher-order nonlinearities in the
             transient response of melanin. These components that are
             higher than linear with respect to the pump or the probe
             introduce intensity-dependent changes to the overall
             response that complicate data analysis. However, our data
             also suggest these nonlinearities might be advantageous to
             in vivo imaging, in that different types of melanins have
             different nonlinear responses. Therefore, methods to
             separate linear from nonlinear components in transient
             absorption measurements might provide additional information
             to aid in the diagnosis of melanoma. We will discuss
             numerical methods for analyzing the various nonlinear
             contributions to pump-probe signals, with the ultimate
             objective of real time analysis using digital signal
             processing techniques. To that end, we have replaced the
             lock in amplifier in our pump-probe microscope with a
             high-speed data acquisition board, and reprogrammed the
             coprocessor field-programmable gate array (FPGA) to perform
             lock-in detection. The FPGA lock-in offers better
             performance than the commercial instrument, in terms of both
             signal to noise ratio and speed. In addition, the
             flexibility of the digital signal processing approach
             enables demodulation of more complicated waveforms, such as
             spread-spectrum sequences, which has the potential to
             accelerate microscopy methods that rely on slow relaxation
             phenomena, such as photothermal and phosphorescence lifetime
             imaging.},
   Doi = {10.1117/12.2187133},
   Key = {fds328177}
}

@article{fds328386,
   Author = {Warren, WS and Warren, WS},
   Title = {Enhancing tissue and cultural heritage imaging with
             ultrafast nonlinear opticsEnhancing tissue and cultural
             heritage imaging with ultrafast nonlinear
             optics},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2014},
   Month = {July},
   ISBN = {9781943580224},
   url = {http://dx.doi.org/10.1364/PHOTONICS.2016.Tu1A.1},
   Doi = {10.1364/PHOTONICS.2016.Tu1A.1},
   Key = {fds328386}
}

@article{fds234287,
   Author = {Park, JK and Fischer, MC and Susumu, K and Therien, MJ and Warren,
             WS},
   Title = {Femtosecond pulse train shaping for accurate two-photon
             excited fluorescence measurements},
   Journal = {Laser Science, LS 2014},
   Year = {2014},
   Month = {January},
   ISBN = {1557522863},
   Abstract = {We report a simple measurement method that exploits pulse
             train shaping to suppress linear contributions to the
             fluorescence, and allows for extraction of the two-photon
             absorption cross sections. © 2014 OSA.},
   Key = {fds234287}
}

@article{fds328178,
   Author = {Degan, S and Wilson, JW and Gainey, CS and Kent, J and Reddick, TL and Nelson, K and Selim, MA and Warren, WS},
   Title = {In vivo label-free examination of early-stage melanoma
             formation.},
   Journal = {Cancer Research},
   Volume = {73},
   Number = {8},
   Year = {2013},
   Month = {April},
   Key = {fds328178}
}

@article{fds328387,
   Author = {Warren, WS},
   Title = {Applications of novel nonlinear imaging: From melanoma
             diagnosis to art restoration},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {244},
   Year = {2012},
   Month = {August},
   Key = {fds328387}
}

@article{fds234288,
   Author = {Matthews, TE and Piletic, I and Selim, MA and Simpson, MJ and Warren,
             WS},
   Title = {Beyond Pathology: Pump-probe imaging of skin slices provides
             additional indicators of melanoma},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {January},
   ISBN = {9781557529091},
   Abstract = {Principal component analysis of images taken with a
             pump-probe scanning microscope resolves eumelanin and
             pheomelanin. Utilizing intrinsic melanin contrast in skin
             slices has revealed significant differences between melanoma
             and other lesions. © 2011 OSA: BODA/NTM/OMP/OTA.},
   Key = {fds234288}
}

@article{fds234289,
   Author = {Samineni, P and Fischer, MC and Liu, HC and Yasuda, R and Warren,
             WS},
   Title = {Nonlinear phase contrast imaging in neuronal
             tissue},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {January},
   ISBN = {9781557529091},
   Abstract = {We demonstrate nonlinear phase contrast imaging in highly
             scattering media using rapid femtosecond pulse shaping of
             mode-locked laser pulses. We will also discuss potential
             applications of this technique for intrinsic functional
             neuronal imaging. © 2011 OSA: BODA/NTM/OMP/OTA.},
   Key = {fds234289}
}

@article{fds328182,
   Author = {Galiana, G and Branca, RT and Jenista, ER and Warren,
             WS},
   Title = {PHYS 363-iMQC-CSI with a single spectroscopic
             dimension},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {236},
   Year = {2008},
   Month = {August},
   Key = {fds328182}
}

@article{fds328183,
   Author = {Jenista, ER and Branca, RT and Frank, A and Warren,
             WS},
   Title = {PHYS 361-Hyperpolarized carbon-carbon intermolecular
             multiple quantum coherences},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {236},
   Year = {2008},
   Month = {August},
   Key = {fds328183}
}

@article{fds328389,
   Author = {Song, J and Warren, WS},
   Title = {PHYS 283-Novel magnetic resonance imaging contrast stemming
             from local resonance frequency variation generated by
             intermolecular multiple quantum coherences},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {236},
   Year = {2008},
   Month = {August},
   Key = {fds328389}
}

@article{fds328390,
   Author = {Warren, WS},
   Title = {PHYS 278-Novel applications and signal enhancement methods
             for detecting intermolecular multiple quantum coherences in
             magnetic resonance},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {236},
   Year = {2008},
   Month = {August},
   Key = {fds328390}
}

@article{fds328391,
   Author = {Chen, YM and Warren, WS},
   Title = {PHYS 370-Probing local anisotropy using mismatched gradient
             spin echoes and intermolecular multiple quantum
             coherences},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {236},
   Year = {2008},
   Month = {August},
   Key = {fds328391}
}

@article{fds328392,
   Author = {Branca, RT and Galiana, G and Warren, WS},
   Title = {PHYS 355-Amplification of dipolar field effects through
             binary modulation of equilibrium magnetization},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {236},
   Year = {2008},
   Month = {August},
   Key = {fds328392}
}

@article{fds328393,
   Author = {Warren, WS},
   Title = {ANYL 385-Enhanced detection of hyperpolarized and
             functionalized MR contrast agents using intermolecular
             coherences},
   Journal = {ACS National Meeting Book of Abstracts},
   Volume = {236},
   Year = {2008},
   Month = {August},
   Key = {fds328393}
}

@article{fds234364,
   Author = {Warren, WS and Miller, A and Ye, T and Liu, H and Fischer, MC and Wagner,
             W},
   Title = {Tissue imaging with shaped femtosecond laser
             pulses},
   Journal = {Springer Series in Chemical Physics},
   Volume = {88},
   Pages = {807-+},
   Year = {2007},
   ISBN = {978-3-540-68779-5},
   ISSN = {0172-6218},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000250104700257&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {Rapid laser pulse shaping permit detection of novel
             molecular signatures such as self- and cross-phase
             modulation or nonlinear absorption. These effects are used
             to discriminate between different melanins in tissue and to
             monitor neuronal activation. © 2009 OSA/FiO/LS/AO/AIOM/COSI/LM/SRS
             2009.},
   Key = {fds234364}
}


%% Journal Articles   
@article{fds329398,
   Author = {Puza, CJ and Warren, WS and Mosca, PJ},
   Title = {Correction to: The changing landscape of dermatology
             practice: melanoma and pump-probe laser microscopy.},
   Journal = {Lasers in Medical Science},
   Volume = {32},
   Number = {9},
   Pages = {2173},
   Year = {2017},
   Month = {December},
   url = {http://dx.doi.org/10.1007/s10103-017-2339-y},
   Abstract = {The published online version contains mistake. Warren S.
             Warren was not included in the author group section.
             Corrected author group section is shown above.},
   Doi = {10.1007/s10103-017-2339-y},
   Key = {fds329398}
}

@article{fds328157,
   Author = {Shen, K and Logan, AWJ and Colell, JFP and Bae, J and Ortiz, GX and Theis,
             T and Warren, WS and Malcolmson, SJ and Wang, Q},
   Title = {Diazirines as Potential Molecular Imaging Tags: Probing the
             Requirements for Efficient and Long-Lived SABRE-Induced
             Hyperpolarization.},
   Journal = {Angewandte Chemie International Edition},
   Volume = {56},
   Number = {40},
   Pages = {12112-12116},
   Year = {2017},
   Month = {September},
   url = {http://dx.doi.org/10.1002/anie.201704970},
   Abstract = {Diazirines are an attractive class of potential molecular
             tags for magnetic resonance imaging owing to their
             biocompatibility and ease of incorporation into a large
             variety of molecules. As recently reported, 15 N2 -diazirine
             can be hyperpolarized by the SABRE-SHEATH method, sustaining
             both singlet and magnetization states, thus offering a path
             to long-lived polarization storage. Herein, we show the
             generality of this approach by illustrating that the
             diazirine tag alone is sufficient for achieving excellent
             signal enhancements with long-lasting polarization. Our
             investigations reveal the critical role of Lewis basic
             additives, including water, on achieving SABRE-promoted
             hyperpolarization. The application of this strategy to a 15
             N2 -diazirine-containing choline derivative demonstrates the
             potential of 15 N2 -diazirines as molecular imaging tags for
             biomedical applications.},
   Doi = {10.1002/anie.201704970},
   Key = {fds328157}
}

@article{fds328155,
   Author = {Shchepin, RV and Goodson, BM and Theis, T and Warren, WS and Chekmenev,
             EY},
   Title = {Toward Hyperpolarized 19 F Molecular Imaging via Reversible
             Exchange with Parahydrogen.},
   Journal = {Chemphyschem},
   Volume = {18},
   Number = {15},
   Pages = {1961-1965},
   Year = {2017},
   Month = {August},
   url = {http://dx.doi.org/10.1002/cphc.201700594},
   Abstract = {Fluorine-19 has high NMR detection sensitivity-similar to
             that of protons-owing to its large gyromagnetic ratio and
             high natural abundance (100 %). Unlike protons, however,
             fluorine-19 (19 F) has a negligible occurrence in biological
             objects, as well as a more sensitive chemical shift. As a
             result, in vivo 19 F NMR spectroscopy and MR imaging offer
             advantages of negligible background signal and sensitive
             reporting of the local molecular environment. Here we report
             on NMR hyperpolarization of 19 F nuclei using reversible
             exchange reactions with parahydrogen gas as the source of
             nuclear spin order. NMR signals of 3-fluoropyridine were
             enhanced by ≈100 fold, corresponding to 0.3 % 19 F
             nuclear spin polarization (at 9.4 T), using about 50 %
             parahydrogen. While future optimization efforts will likely
             significantly increase the hyperpolarization levels, we
             already demonstrate the utility of 19 F hyperpolarization
             for high-resolution hyperpolarized 19 F imaging and
             hyperpolarized 19 F pH sensing.},
   Doi = {10.1002/cphc.201700594},
   Key = {fds328155}
}

@article{fds328353,
   Author = {Wilson, JW and Robles, FE and Deb, S and Warren, WS and Fischer,
             MC},
   Title = {Comparison of pump-probe and hyperspectral imaging in
             unstained histology sections of pigmented
             lesions.},
   Journal = {Biomedical Optics Express},
   Volume = {8},
   Number = {8},
   Pages = {3882-3890},
   Year = {2017},
   Month = {August},
   url = {http://dx.doi.org/10.1364/boe.8.003882},
   Abstract = {Microscopic variations in melanin composition can be mapped
             through linear and nonlinear optical responses. Though
             instrumentation to measure linear attenuation is simple and
             inexpensive, the nonlinear response provides more degrees of
             freedom with which to spectroscopically resolve pigments.
             The objective of this study is to assess differences in
             imaging melanin contrast by comparing hyperspectral (linear)
             versus pump-probe (nonlinear) microscopy of unstained
             histology sections of pigmented lesions. The images and
             analysis we have presented here show that pump-probe
             uncovers a greater variation in pigment composition,
             compared with hyperspectral microscopy, and that the two
             methods yield complimentary biochemical information.},
   Doi = {10.1364/boe.8.003882},
   Key = {fds328353}
}

@article{fds328156,
   Author = {Zhou, Z and Yu, J and Colell, JFP and Laasner, R and Logan, A and Barskiy,
             DA and Shchepin, RV and Chekmenev, EY and Blum, V and Warren, WS and Theis,
             T},
   Title = {Long-Lived 13C2 Nuclear Spin States Hyperpolarized by
             Parahydrogen in Reversible Exchange at Microtesla
             Fields.},
   Journal = {Journal of Physical Chemistry Letters},
   Volume = {8},
   Number = {13},
   Pages = {3008-3014},
   Year = {2017},
   Month = {July},
   url = {http://dx.doi.org/10.1021/acs.jpclett.7b00987},
   Abstract = {Parahydrogen is an inexpensive and readily available source
             of hyperpolarization used to enhance magnetic resonance
             signals by up to four orders of magnitude above thermal
             signals obtained at ∼10 T. A significant challenge for
             applications is fast signal decay after hyperpolarization.
             Here we use parahydrogen-based polarization transfer
             catalysis at microtesla fields (first introduced as
             SABRE-SHEATH) to hyperpolarize 13C2 spin pairs and find
             decay time constants of 12 s for magnetization at 0.3 mT,
             which are extended to 2 min at that same field, when
             long-lived singlet states are hyperpolarized instead.
             Enhancements over thermal at 8.5 T are between 30 and 170
             fold (0.02 to 0.12% polarization). We control the spin
             dynamics of polarization transfer by choice of microtesla
             field, allowing for deliberate hyperpolarization of either
             magnetization or long-lived singlet states. Density
             functional theory calculations and experimental evidence
             identify two energetically close mechanisms for polarization
             transfer: First, a model that involves direct binding of the
             13C2 pair to the polarization transfer catalyst and, second,
             a model transferring polarization through auxiliary protons
             in substrates.},
   Doi = {10.1021/acs.jpclett.7b00987},
   Key = {fds328156}
}

@article{fds328158,
   Author = {Colell, JFP and Emondts, M and Logan, AWJ and Shen, K and Bae, J and Shchepin, RV and Ortiz, GX and Spannring, P and Wang, Q and Malcolmson,
             SJ and Chekmenev, EY and Feiters, MC and Rutjes, FPJT and Blümich, B and Theis, T and Warren, WS},
   Title = {Direct Hyperpolarization of Nitrogen-15 in Aqueous Media
             with Parahydrogen in Reversible Exchange.},
   Journal = {Journal of the American Chemical Society},
   Volume = {139},
   Number = {23},
   Pages = {7761-7767},
   Year = {2017},
   Month = {June},
   url = {http://dx.doi.org/10.1021/jacs.7b00569},
   Abstract = {Signal amplification by reversible exchange (SABRE) is an
             inexpensive, fast, and even continuous hyperpolarization
             technique that uses para-hydrogen as hyperpolarization
             source. However, current SABRE faces a number of stumbling
             blocks for translation to biochemical and clinical settings.
             Difficulties include inefficient polarization in water,
             relatively short-lived 1H-polarization, and relatively
             limited substrate scope. Here we use a water-soluble
             polarization transfer catalyst to hyperpolarize nitrogen-15
             in a variety of molecules with SABRE-SHEATH (SABRE in shield
             enables alignment transfer to heteronuclei). This strategy
             works in pure H2O or D2O solutions, on substrates that could
             not be hyperpolarized in traditional 1H-SABRE experiments,
             and we record 15N T1 relaxation times of up to 2
             min.},
   Doi = {10.1021/jacs.7b00569},
   Key = {fds328158}
}

@article{fds328159,
   Author = {Barskiy, DA and Shchepin, RV and Tanner, CPN and Colell, JFP and Goodson, BM and Theis, T and Warren, WS and Chekmenev,
             EY},
   Title = {The Absence of Quadrupolar Nuclei Facilitates Efficient 13 C
             Hyperpolarization via Reversible Exchange with
             Parahydrogen.},
   Journal = {Chemphyschem},
   Volume = {18},
   Number = {12},
   Pages = {1493-1498},
   Year = {2017},
   Month = {June},
   url = {http://dx.doi.org/10.1002/cphc.201700416},
   Abstract = {Nuclear spin hyperpolarization techniques are
             revolutionizing the field of 13 C molecular MRI. While
             dissolution dynamic nuclear polarization (d-DNP) is
             currently the leading technique, it is generally slow
             (requiring ≈1 h) and costly (≈$USD106 ). As a
             consequence of carbon's central place in biochemistry,
             tremendous progress using 13 C d-DNP bioimaging has been
             demonstrated to date including a number of clinical trials.
             Despite numerous attempts to develop alternatives to d-DNP,
             the competing methods have faced significant translational
             challenges. Efficient hyperpolarization of 15 N, 31 P, and
             other heteronuclei using signal amplification by reversible
             exchange (SABRE) has been reported in 2015, but extension of
             this technique to 13 C has proven to be challenging. Here,
             we present efficient hyperpolarization of 13 C nuclei using
             micro-Tesla SABRE. Up to ca. 6700-fold enhancement of
             nuclear spin polarization at 8.45 T is achieved within
             seconds, corresponding to P13C ≈4.4 % using 50 %
             parahydrogen (P13C >14 % would be feasible using more
             potent ≈100 % parahydrogen). Importantly, the 13 C
             polarization achieved via SABRE strongly depends not only
             upon spin-lattice relaxation, but also upon the presence of
             15 N (I=1/2) versus quadrupolar 14 N (I=1) spins in the site
             binding the hexacoordinate Ir atom of the catalytic complex.
             We show that different 13 C nuclei in the test molecular
             frameworks-pyridine and acetonitrile-can be hyperpolarized,
             including 13 C sites up to five chemical bonds away from the
             exchangeable hydrides. The presented approach is highly
             scalable and can be applied to a rapidly growing number of
             biomolecules amendable to micro-Tesla SABRE.},
   Doi = {10.1002/cphc.201700416},
   Key = {fds328159}
}

@article{fds328160,
   Author = {Robles, FE and Deb, S and Fischer, MC and Warren, WS and Selim,
             MA},
   Title = {Label-Free Imaging of Female Genital Tract Melanocytic
             Lesions With Pump-Probe Microscopy: A Promising Diagnostic
             Tool.},
   Journal = {Journal of Lower Genital Tract Disease},
   Volume = {21},
   Number = {2},
   Pages = {137-144},
   Year = {2017},
   Month = {April},
   url = {http://dx.doi.org/10.1097/lgt.0000000000000290},
   Abstract = {Melanomas of the female genital tract present a unique
             clinical challenge. Not only are these lesions in an
             anatomically sensitive area, but also they tend to be
             multifocal and have high recurrence rates. Furthermore,
             several benign melanocytic proliferations resemble
             early-stage melanoma clinically and/or histopathologically.
             Thus, there is a significant need for additional tools that
             can help correctly diagnose and stage these lesions. Here,
             we quantitatively and nondestructively analyze the chemical
             composition of melanin in excised pigmented lesions of the
             female genital tract using pump-probe microscopy, a
             high-resolution optical imaging technique that is sensitive
             to many biochemical properties of melanin.Thirty-one thin
             (~5 μm) tissue sections previously excised from female
             genital tract melanocytic lesions were imaged with
             pump-probe microscopy and analyzed.We find significant
             quantitative differences in melanin type and structure
             between melanoma and nonmalignant melanocytic
             proliferations. Our analysis also suggests a link between
             the molecular signatures of melanins and lesion-specific
             genetic mutations. Finally, significant differences are
             found between metastatic and nonmetastatic melanomas. The
             limitations of this work include the fact that molecular
             information is restricted to melanin pigment and the sample
             size is relatively small.Pump-probe microscopy provides
             unique information regarding the biochemical composition of
             genital tract melanocytic lesions, which can be used to
             improve the diagnosis and staging of vulvar
             melanomas.},
   Doi = {10.1097/lgt.0000000000000290},
   Key = {fds328160}
}

@article{fds328161,
   Author = {Colell, JFP and Logan, AWJ and Zhou, Z and Shchepin, RV and Barskiy, DA and Ortiz, GX and Wang, Q and Malcolmson, SJ and Chekmenev, EY and Warren,
             WS and Theis, T},
   Title = {Generalizing, Extending, and Maximizing Nitrogen-15
             Hyperpolarization Induced by Parahydrogen in Reversible
             Exchange.},
   Journal = {The Journal of Physical Chemistry C},
   Volume = {121},
   Number = {12},
   Pages = {6626-6634},
   Year = {2017},
   Month = {March},
   url = {http://dx.doi.org/10.1021/acs.jpcc.6b12097},
   Abstract = {Signal Amplification by Reversible Exchange (SABRE) is a
             fast and convenient NMR hyperpolarization method that uses
             cheap and readily available para-hydrogen as a
             hyperpolarization source. SABRE can hyperpolarize protons
             and heteronuclei. Here we focus on the heteronuclear variant
             introduced as SABRE-SHEATH (SABRE in SHield Enables
             Alignment Transfer to Heteronuclei) and nitrogen-15 targets
             in particular. We show that 15N-SABRE works more efficiently
             and on a wider range of substrates than 1H-SABRE, greatly
             generalizing the SABRE approach. In addition, we show that
             nitrogen-15 offers significantly extended T1 times of up to
             12 minutes. Long T1 times enable higher hyperpolarization
             levels but also hold the promise of hyperpolarized molecular
             imaging for several tens of minutes. Detailed
             characterization and optimization are presented, leading to
             nitrogen-15 polarization levels in excess of 10% on several
             compounds.},
   Doi = {10.1021/acs.jpcc.6b12097},
   Key = {fds328161}
}

@article{fds328162,
   Author = {Robles, FE and Zhou, KC and Fischer, MC and Warren,
             WS},
   Title = {Stimulated Raman scattering spectroscopic optical coherence
             tomography},
   Journal = {Optica},
   Volume = {4},
   Number = {2},
   Pages = {243-243},
   Year = {2017},
   Month = {February},
   url = {http://dx.doi.org/10.1364/OPTICA.4.000243},
   Doi = {10.1364/OPTICA.4.000243},
   Key = {fds328162}
}

@article{fds328163,
   Author = {Thompson, A and Robles, FE and Wilson, JW and Deb, S and Calderbank, R and Warren, WS},
   Title = {Dual-wavelength pump-probe microscopy analysis of melanin
             composition.},
   Journal = {Scientific Reports},
   Volume = {6},
   Pages = {36871},
   Year = {2016},
   Month = {November},
   url = {http://dx.doi.org/10.1038/srep36871},
   Abstract = {Pump-probe microscopy is an emerging technique that provides
             detailed chemical information of absorbers with
             sub-micrometer spatial resolution. Recent work has shown
             that the pump-probe signals from melanin in human skin
             cancers correlate well with clinical concern, but it has
             been difficult to infer the molecular origins of these
             differences. Here we develop a mathematical framework to
             describe the pump-probe dynamics of melanin in human
             pigmented tissue samples, which treats the ensemble of
             individual chromophores that make up melanin as Gaussian
             absorbers with bandwidth related via Frenkel excitons. Thus,
             observed signals result from an interplay between the
             spectral bandwidths of the individual underlying
             chromophores and spectral proximity of the pump and probe
             wavelengths. The model is tested using a dual-wavelength
             pump-probe approach and a novel signal processing method
             based on gnomonic projections. Results show signals can be
             described by a single linear transition path with different
             rates of progress for different individual pump-probe
             wavelength pairs. Moreover, the combined dual-wavelength
             data shows a nonlinear transition that supports our
             mathematical framework and the excitonic model to describe
             the optical properties of melanin. The novel gnomonic
             projection analysis can also be an attractive generic tool
             for analyzing mixing paths in biomolecular and analytical
             chemistry.},
   Doi = {10.1038/srep36871},
   Key = {fds328163}
}

@article{fds328398,
   Author = {Warren, WS},
   Title = {Ahmed Hassan Zewail (1946-2016) OBITUARY},
   Journal = {Nature},
   Volume = {537},
   Number = {7619},
   Pages = {168-168},
   Year = {2016},
   Month = {September},
   Key = {fds328398}
}

@article{fds328399,
   Author = {Warren, WS},
   Title = {Obituary: Ahmed Hassan Zewail (1946-2016).},
   Journal = {Nature},
   Volume = {537},
   Number = {7619},
   Pages = {168},
   Year = {2016},
   Month = {September},
   url = {http://dx.doi.org/10.1038/537168a},
   Doi = {10.1038/537168a},
   Key = {fds328399}
}

@article{fds328164,
   Author = {Villafana, TE and Delaney, JK and Warren, WS and Fischer,
             MC},
   Title = {High-resolution, three-dimensional imaging of pigments and
             support in paper and textiles},
   Journal = {Journal of Cultural Heritage},
   Volume = {20},
   Pages = {583-588},
   Year = {2016},
   Month = {July},
   url = {http://dx.doi.org/10.1016/j.culher.2016.02.003},
   Doi = {10.1016/j.culher.2016.02.003},
   Key = {fds328164}
}

@article{fds328165,
   Author = {Logan, AWJ and Theis, T and Colell, JFP and Warren, WS and Malcolmson,
             SJ},
   Title = {Hyperpolarization of Nitrogen-15 Schiff Bases by Reversible
             Exchange Catalysis with para-Hydrogen.},
   Journal = {Chemistry - A European Journal},
   Volume = {22},
   Number = {31},
   Pages = {10777-10781},
   Year = {2016},
   Month = {July},
   url = {http://dx.doi.org/10.1002/chem.201602393},
   Abstract = {NMR with thermal polarization requires relatively
             concentrated samples, particularly for nuclei with low
             abundance and low gyromagnetic ratios, such as (15) N. We
             expand the substrate scope of SABRE, a recently introduced
             hyperpolarization method, to allow access to (15) N-enriched
             Schiff bases. These substrates show fractional (15) N
             polarization levels of up to 2 % while having only minimal
             (1) H enhancements.},
   Doi = {10.1002/chem.201602393},
   Key = {fds328165}
}

@article{fds328166,
   Author = {Barskiy, DA and Shchepin, RV and Coffey, AM and Theis, T and Warren, WS and Goodson, BM and Chekmenev, EY},
   Title = {Over 20% (15)N Hyperpolarization in Under One Minute for
             Metronidazole, an Antibiotic and Hypoxia
             Probe.},
   Journal = {Journal of the American Chemical Society},
   Volume = {138},
   Number = {26},
   Pages = {8080-8083},
   Year = {2016},
   Month = {July},
   url = {http://dx.doi.org/10.1021/jacs.6b04784},
   Abstract = {Direct NMR hyperpolarization of naturally abundant (15)N
             sites in metronidazole is demonstrated using SABRE-SHEATH
             (Signal Amplification by Reversible Exchange in SHield
             Enables Alignment Transfer to Heteronuclei). In only a few
             tens of seconds, nuclear spin polarization P(15)N of up to
             ∼24% is achieved using parahydrogen with 80% para fraction
             corresponding to P(15)N ≈ 32% if ∼100% parahydrogen were
             employed (which would translate to a signal enhancement of
             ∼0.1-million-fold at 9.4 T). In addition to this
             demonstration on the directly binding (15)N site (using
             J(2)H-(15)N), we also hyperpolarized more distant (15)N
             sites in metronidazole using longer-range spin-spin
             couplings (J(4)H-(15)N and J(5)H-(15)N). Taken together,
             these results significantly expand the range of molecular
             structures and sites amenable to hyperpolarization via
             low-cost parahydrogen-based methods. In particular,
             hyperpolarized nitroimidazole and its derivatives have
             powerful potential applications such as direct in vivo
             imaging of mechanisms of action or hypoxia
             sensing.},
   Doi = {10.1021/jacs.6b04784},
   Key = {fds328166}
}

@article{fds328167,
   Author = {Shchepin, RV and Barskiy, DA and Coffey, AM and Theis, T and Shi, F and Warren, WS and Goodson, BM and Chekmenev, EY},
   Title = {15N Hyperpolarization of Imidazole-15N2 for Magnetic
             Resonance pH Sensing via SABRE-SHEATH.},
   Journal = {ACS sensors},
   Volume = {1},
   Number = {6},
   Pages = {640-644},
   Year = {2016},
   Month = {June},
   Abstract = {15N nuclear spins of imidazole-15N2 were hyperpolarized
             using NMR signal amplification by reversible exchange in
             shield enables alignment transfer to heteronuclei
             (SABRE-SHEATH). A 15N NMR signal enhancement of ∼2000-fold
             at 9.4 T is reported using parahydrogen gas (∼50% para-)
             and ∼0.1 M imidazole-15N2 in methanol:aqueous buffer
             (∼1:1). Proton binding to a 15N site of imidazole occurs
             at physiological pH (pKa ∼ 7.0), and the binding event
             changes the 15N isotropic chemical shift by ∼30 ppm. These
             properties are ideal for in vivo pH sensing. Additionally,
             imidazoles have low toxicity and are readily incorporated
             into a wide range of biomolecules. 15N-Imidazole
             SABRE-SHEATH hyperpolarization potentially enables pH
             sensing on scales ranging from peptide and protein molecules
             to living organisms.},
   Key = {fds328167}
}

@article{fds234281,
   Author = {Davis, RM and Zhou, Z and Chung, H and Warren, WS},
   Title = {Multi-spin echo spatial encoding provides three-fold
             improvement of temperature precision during intermolecular
             zero quantum thermometry.},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {75},
   Number = {5},
   Pages = {1958-1966},
   Year = {2016},
   Month = {May},
   ISSN = {0740-3194},
   url = {http://dx.doi.org/10.1002/mrm.25789},
   Abstract = {Intermolecular multiple quantum coherences (iMQCs) are a
             source of MR contrast with applications including
             temperature imaging, anisotropy mapping, and brown fat
             imaging. Because all applications are limited by
             signal-to-noise ratio (SNR), we developed a pulse sequence
             that detects intermolecular zero quantum coherences with
             improved SNR.A previously developed pulse sequence that
             detects iMQCs, HOMOGENIZED with off resonance transfer
             (HOT), was modified with a multi-spin echo spatial encoding
             scheme (MSE-HOT). MSE-HOT uses a series of refocusing pulses
             to generate a stack of images that are averaged in
             postprocessing for higher SNR. MSE-HOT performance was
             quantified by measuring its temperature accuracy and
             precision during hyperthermia of ex vivo red bone marrow
             samples.MSE-HOT yielded a three-fold improvement in
             temperature precision relative to previous pulse sequences.
             Sources of improved precision were 1) echo averaging and 2)
             suppression of J-coupling in the methylene protons of fat.
             MSE-HOT measured temperature change with an accuracy of
             0.6°C.MSE-HOT improved the temperature accuracy and
             precision of HOT to a level that is sufficient for
             hyperthermia of bone marrow.},
   Doi = {10.1002/mrm.25789},
   Key = {fds234281}
}

@article{fds312615,
   Author = {Theis, T and Ortiz, GX and Logan, AWJ and Claytor, KE and Feng, Y and Huhn,
             WP and Blum, V and Malcolmson, SJ and Chekmenev, EY and Wang, Q and Warren,
             WS},
   Title = {Direct and cost-efficient hyperpolarization of long-lived
             nuclear spin states on universal (15)N2-diazirine molecular
             tags.},
   Journal = {Science Advances},
   Volume = {2},
   Number = {3},
   Pages = {e1501438},
   Year = {2016},
   Month = {March},
   url = {http://hdl.handle.net/10161/11770 Duke open
             access},
   Abstract = {Conventional magnetic resonance (MR) faces serious
             sensitivity limitations which can be overcome by
             hyperpolarization methods, but the most common method
             (dynamic nuclear polarization) is complex and expensive, and
             applications are limited by short spin lifetimes (typically
             seconds) of biologically relevant molecules. We use a
             recently developed method, SABRE-SHEATH, to directly
             hyperpolarize (15)N2 magnetization and long-lived (15)N2
             singlet spin order, with signal decay time constants of 5.8
             and 23 minutes, respectively. We find >10,000-fold
             enhancements generating detectable nuclear MR signals that
             last for over an hour. (15)N2-diazirines represent a class
             of particularly promising and versatile molecular tags, and
             can be incorporated into a wide range of biomolecules
             without significantly altering molecular
             function.},
   Doi = {10.1126/sciadv.1501438},
   Key = {fds312615}
}

@article{fds328169,
   Author = {Fischer, MC and Wilson, JW and Robles, FE and Warren,
             WS},
   Title = {Invited Review Article: Pump-probe microscopy.},
   Journal = {Review of Scientific Instruments},
   Volume = {87},
   Number = {3},
   Pages = {031101},
   Year = {2016},
   Month = {March},
   url = {http://dx.doi.org/10.1063/1.4943211},
   Abstract = {Multiphoton microscopy has rapidly gained popularity in
             biomedical imaging and materials science because of its
             ability to provide three-dimensional images at high spatial
             and temporal resolution even in optically scattering
             environments. Currently the majority of commercial and
             home-built devices are based on two-photon fluorescence and
             harmonic generation contrast. These two contrast mechanisms
             are relatively easy to measure but can access only a limited
             range of endogenous targets. Recent developments in fast
             laser pulse generation, pulse shaping, and detection
             technology have made accessible a wide range of optical
             contrasts that utilize multiple pulses of different colors.
             Molecular excitation with multiple pulses offers a large
             number of adjustable parameters. For example, in two-pulse
             pump-probe microscopy, one can vary the wavelength of each
             excitation pulse, the detection wavelength, the timing
             between the excitation pulses, and the detection gating
             window after excitation. Such a large parameter space can
             provide much greater molecular specificity than existing
             single-color techniques and allow for structural and
             functional imaging without the need for exogenous dyes and
             labels, which might interfere with the system under study.
             In this review, we provide a tutorial overview, covering
             principles of pump-probe microscopy and experimental setup,
             challenges associated with signal detection and data
             processing, and an overview of applications.},
   Doi = {10.1063/1.4943211},
   Key = {fds328169}
}

@article{fds328170,
   Author = {Zhou, Z and Claytor, K and Warren, WS and Theis, T},
   Title = {Accessing long lived (1)H states via (2)H
             couplings.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {263},
   Pages = {108-115},
   Year = {2016},
   Month = {February},
   url = {http://dx.doi.org/10.1016/j.jmr.2015.12.020},
   Abstract = {In this paper we demonstrate long-lived states involving a
             pair of chemically equivalent protons, with lifetimes ∼30
             times T1 up to a total lifetime of ∼117s at high field
             (8.45T). This is demonstrated on trans-ethylene-d2 in
             solution, where magnetic inequivalence gives access to the
             long-lived states. It is shown that the remaining J-coupling
             between the two quadrupolar deuterium spins, JQQ, splits the
             conditions for optimally generating proton singlet states.
             Detailed simulations of the spin evolution are performed,
             shedding light on the coherent evolution during
             singlet-triplet conversion as well as on the incoherent
             evolution that causes relaxation. Subsequently, the
             simulations are compared with experimental results
             validating the theoretical insights. Possible applications
             include storage of hyperpolarization in the proton
             long-lived state. Of particular interest may be utilization
             of parahydrogen induced polarization to directly induce the
             examined long-lived states.},
   Doi = {10.1016/j.jmr.2015.12.020},
   Key = {fds328170}
}

@article{fds328172,
   Author = {Robles, FE and Fischer, MC and Warren, WS},
   Title = {Dispersion-based stimulated Raman scattering spectroscopy,
             holography, and optical coherence tomography.},
   Journal = {Optics express},
   Volume = {24},
   Number = {1},
   Pages = {485-498},
   Year = {2016},
   Month = {January},
   url = {http://dx.doi.org/10.1364/oe.24.000485},
   Abstract = {Stimulated Raman scattering (SRS) enables fast, high
             resolution imaging of chemical constituents important to
             biological structures and functional processes, both in a
             label-free manner and using exogenous biomarkers. While this
             technology has shown remarkable potential, it is currently
             limited to point scanning and can only probe a few Raman
             bands at a time (most often, only one). In this work we take
             a fundamentally different approach to detecting the small
             nonlinear signals based on dispersion effects that accompany
             the loss/gain processes in SRS. In this proof of concept, we
             demonstrate that the dispersive measurements are more robust
             to noise compared to amplitude-based measurements, which
             then permit spectral or spatial multiplexing (potentially
             both, simultaneously). Finally, we illustrate how this
             method may enable different strategies for biochemical
             imaging using phase microscopy and optical coherence
             tomography.},
   Doi = {10.1364/oe.24.000485},
   Key = {fds328172}
}

@article{fds328174,
   Author = {Robles, FE and Deb, S and Wilson, JW and Gainey, CS and Selim, MA and Mosca, PJ and Tyler, DS and Fischer, MC and Warren,
             WS},
   Title = {Pump-probe imaging of pigmented cutaneous melanoma primary
             lesions gives insight into metastatic potential.},
   Journal = {Biomedical Optics Express},
   Volume = {6},
   Number = {9},
   Pages = {3631-3645},
   Year = {2015},
   Month = {September},
   url = {http://dx.doi.org/10.1364/boe.6.003631},
   Abstract = {Metastatic melanoma is associated with a poor prognosis, but
             no method reliably predicts which melanomas of a given stage
             will ultimately metastasize and which will not. While
             sentinel lymph node biopsy (SLNB) has emerged as the most
             powerful predictor of metastatic disease, the majority of
             people dying from metastatic melanoma still have a negative
             SLNB. Here we analyze pump-probe microscopy images of thin
             biopsy slides of primary melanomas to assess their
             metastatic potential. Pump-probe microscopy reveals detailed
             chemical information of melanin with subcellular spatial
             resolution. Quantification of the molecular signatures
             without reference standards is achieved using a geometrical
             representation of principal component analysis. Melanin
             structure is analyzed in unison with the chemical
             information by applying principles of mathematical
             morphology. Results show that melanin in metastatic primary
             lesions has lower chemical diversity than non-metastatic
             primary lesions, and contains two distinct phenotypes that
             are indicative of aggressive disease. Further, the
             mathematical morphology analysis reveals melanin in
             metastatic primary lesions has a distinct "dusty" quality.
             Finally, a statistical analysis shows that the combination
             of the chemical information with spatial structures predicts
             metastatic potential with much better sensitivity than SLNB
             and high specificity, suggesting pump-probe microscopy can
             be an important tool to help predict the metastatic
             potential of melanomas.},
   Doi = {10.1364/boe.6.003631},
   Key = {fds328174}
}

@article{fds234336,
   Author = {Crumbliss, AL and Franz, KJ and Thiele, DJ},
   Title = {Preface. Biometals 2014--Proceedings of the 9th
             International Symposium Biometals 2014 at Duke University,
             Durham, NC, USA.},
   Journal = {BioMetals},
   Volume = {28},
   Number = {3},
   Pages = {431},
   Year = {2015},
   Month = {June},
   ISSN = {1057-2732},
   url = {http://dx.doi.org/10.1007/s10534-015-9854-8},
   Doi = {10.1007/s10534-015-9854-8},
   Key = {fds234336}
}

@article{fds234282,
   Author = {Shchepin, RV and Truong, ML and Theis, T and Coffey, AM and Shi, F and Waddell, KW and Warren, WS and Goodson, BM and Chekmenev,
             EY},
   Title = {Hyperpolarization of "Neat" Liquids by NMR Signal
             Amplification by Reversible Exchange.},
   Journal = {Journal of Physical Chemistry Letters},
   Volume = {6},
   Number = {10},
   Pages = {1961-1967},
   Year = {2015},
   Month = {May},
   url = {http://dx.doi.org/10.1021/acs.jpclett.5b00782},
   Abstract = {We report NMR Signal Amplification by Reversible Exchange
             (SABRE) hyperpolarization of the rare isotopes in "neat"
             liquids, each composed only of an otherwise pure target
             compound with isotopic natural abundance (n.a.) and
             millimolar concentrations of dissolved catalyst. Pyridine
             (Py) or Py derivatives are studied at 0.4% isotopic natural
             abundance ¹⁵N, deuterated, ¹⁵N enriched, and in
             various combinations using the SABRE-SHEATH variant
             (microTesla magnetic fields to permit direct ¹⁵N
             polarization from parahydrogen via reversible binding and
             exchange with an Ir catalyst). We find that the dilute n.a.
             ¹⁵N spin bath in Py still channels spin order from
             parahydrogen to dilute ¹⁵N spins, without polarization
             losses due to the presence of ¹⁴N or ²H. We demonstrate
             P(15N) ≈ 1% (a gain of 2900 fold relative to thermal
             polarization at 9.4 T) at high substrate concentrations.
             This fundamental finding has a significant practical benefit
             for screening potentially hyperpolarizable contrast agents
             without labeling. The capability of screening at n.a. level
             of ¹⁵N is demonstrated on examples of mono- and
             dimethyl-substituted Py (picolines and lutidines previously
             identified as promising pH sensors), showing that the
             presence of a methyl group in the ortho position
             significantly decreases SABRE hyperpolarization.},
   Doi = {10.1021/acs.jpclett.5b00782},
   Key = {fds234282}
}

@article{fds234290,
   Author = {Wilson, JW and Degan, S and Gainey, CS and Mitropoulos, T and Simpson,
             MJ and Zhang, JY and Warren, WS},
   Title = {Comparing in vivo pump-probe and multiphoton fluorescence
             microscopy of melanoma and pigmented lesions.},
   Journal = {Journal of Biomedical Optics},
   Volume = {20},
   Number = {5},
   Pages = {051012},
   Year = {2015},
   Month = {May},
   ISSN = {1083-3668},
   url = {http://dx.doi.org/10.1117/1.jbo.20.5.051012},
   Abstract = {We demonstrate a multimodal approach that combines a
             pump-probe with confocal reflectance and multiphoton
             autofluorescence microscopy. Pump-probe microscopy has been
             proven to be of great value in analyzing thin tissue
             sections of pigmented lesions, as it produces molecular
             contrast which is inaccessible by other means. However, the
             higher optical intensity required to overcome scattering in
             thick tissue leads to higher-order nonlinearities in the
             optical response of melanin (e.g., two-photon pump and
             one-photon probe) that present additional challenges for
             interpreting the data. We show that analysis of pigment
             composition in vivo must carefully account for signal terms
             that are nonlinear with respect to the pump and probe
             intensities. We find that pump-probe imaging gives useful
             contrast for pigmented structures over a large range of
             spatial scales (100 μm to 1 cm), making it a potentially
             useful tool for tracking the progression of pigmented
             lesions without the need to introduce exogenous contrast
             agents.},
   Doi = {10.1117/1.jbo.20.5.051012},
   Key = {fds234290}
}

@article{fds234284,
   Author = {Truong, ML and Theis, T and Coffey, AM and Shchepin, RV and Waddell, KW and Shi, F and Goodson, BM and Warren, WS and Chekmenev,
             EY},
   Title = {(15)N Hyperpolarization by Reversible Exchange Using
             SABRE-SHEATH.},
   Journal = {The Journal of Physical Chemistry C},
   Volume = {119},
   Number = {16},
   Pages = {8786-8797},
   Year = {2015},
   Month = {April},
   ISSN = {1932-7447},
   url = {http://dx.doi.org/10.1021/acs.jpcc.5b01799},
   Abstract = {NMR signal amplification by reversible exchange (SABRE) is a
             NMR hyperpolarization technique that enables nuclear spin
             polarization enhancement of molecules via concurrent
             chemical exchange of a target substrate and parahydrogen
             (the source of spin order) on an iridium catalyst. Recently,
             we demonstrated that conducting SABRE in microtesla fields
             provided by a magnetic shield enables up to 10%
             (15)N-polarization (Theis, T.; et al. J. Am. Chem. Soc.2015,
             137, 1404). Hyperpolarization on (15)N (and heteronuclei in
             general) may be advantageous because of the long-lived
             nature of the hyperpolarization on (15)N relative to the
             short-lived hyperpolarization of protons conventionally
             hyperpolarized by SABRE, in addition to wider chemical shift
             dispersion and absence of background signal. Here we show
             that these unprecedented polarization levels enable (15)N
             magnetic resonance imaging. We also present a theoretical
             model for the hyperpolarization transfer to heteronuclei,
             and detail key parameters that should be optimized for
             efficient (15)N-hyperpolarization. The effects of
             parahydrogen pressure, flow rate, sample temperature,
             catalyst-to-substrate ratio, relaxation time (T1), and
             reversible oxygen quenching are studied on a test system of
             (15)N-pyridine in methanol-d4. Moreover, we demonstrate the
             first proof-of-principle (13)C-hyperpolarization using this
             method. This simple hyperpolarization scheme only requires
             access to parahydrogen and a magnetic shield, and it
             provides large enough signal gains to enable one of the
             first (15)N images (2 × 2 mm(2) resolution). Importantly,
             this method enables hyperpolarization of molecular sites
             with NMR T1 relaxation times suitable for biomedical imaging
             and spectroscopy.},
   Doi = {10.1021/acs.jpcc.5b01799},
   Key = {fds234284}
}

@article{fds234285,
   Author = {Wilson, JW and Park, JK and Warren, WS and Fischer,
             MC},
   Title = {Flexible digital signal processing architecture for
             narrowband and spread-spectrum lock-in detection in
             multiphoton microscopy and time-resolved
             spectroscopy.},
   Journal = {Review of Scientific Instruments},
   Volume = {86},
   Number = {3},
   Pages = {033707},
   Year = {2015},
   Month = {March},
   ISSN = {0034-6748},
   url = {http://dx.doi.org/10.1063/1.4916261},
   Abstract = {The lock-in amplifier is a critical component in many
             different types of experiments, because of its ability to
             reduce spurious or environmental noise components by
             restricting detection to a single frequency and phase. One
             example application is pump-probe microscopy, a multiphoton
             technique that leverages excited-state dynamics for imaging
             contrast. With this application in mind, we present here the
             design and implementation of a high-speed lock-in amplifier
             on the field-programmable gate array (FPGA) coprocessor of a
             data acquisition board. The most important advantage is the
             inherent ability to filter signals based on more complex
             modulation patterns. As an example, we use the flexibility
             of the FPGA approach to enable a novel pump-probe detection
             scheme based on spread-spectrum communications
             techniques.},
   Doi = {10.1063/1.4916261},
   Key = {fds234285}
}

@article{fds234286,
   Author = {Theis, T and Truong, ML and Coffey, AM and Shchepin, RV and Waddell, KW and Shi, F and Goodson, BM and Warren, WS and Chekmenev,
             EY},
   Title = {Microtesla SABRE enables 10% nitrogen-15 nuclear spin
             polarization.},
   Journal = {Journal of the American Chemical Society},
   Volume = {137},
   Number = {4},
   Pages = {1404-1407},
   Year = {2015},
   Month = {February},
   ISSN = {0002-7863},
   url = {http://dx.doi.org/10.1021/ja512242d},
   Abstract = {Parahydrogen is demonstrated to efficiently transfer its
             nuclear spin hyperpolarization to nitrogen-15 in pyridine
             and nicotinamide (vitamin B(3) amide) by conducting "signal
             amplification by reversible exchange" (SABRE) at microtesla
             fields within a magnetic shield. Following transfer of the
             sample from the magnetic shield chamber to a conventional
             NMR spectrometer, the (15)N NMR signals for these molecules
             are enhanced by ∼30,000- and ∼20,000-fold at 9.4 T,
             corresponding to ∼10% and ∼7% nuclear spin polarization,
             respectively. This method, dubbed "SABRE in shield enables
             alignment transfer to heteronuclei" or "SABRE-SHEATH",
             promises to be a simple, cost-effective way to hyperpolarize
             heteronuclei. It may be particularly useful for in vivo
             applications because of longer hyperpolarization lifetimes,
             lack of background signal, and facile chemical-shift
             discrimination of different species.},
   Doi = {10.1021/ja512242d},
   Key = {fds234286}
}

@article{fds234280,
   Author = {Davis, RM and Warren, WS},
   Title = {Intermolecular zero quantum coherences enable accurate
             temperature imaging in red bone marrow},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {74},
   Number = {1},
   Pages = {63-70},
   Year = {2015},
   Month = {January},
   ISSN = {0740-3194},
   url = {http://dx.doi.org/10.1002/mrm.25372},
   Abstract = {© 2014 Wiley Periodicals, Inc. Magn Reson Med 74:63-70,
             2015. © 2014 Wiley Periodicals, Inc. © 2014 Wiley
             Periodicals, Inc. Purpose Red bone marrow metastases are
             common in breast and prostate cancer patients, but those
             metastases are currently incurable. Recent developments show
             that hyperthermia could be a successful treatment for bone
             metastasis, but thermometry remains difficult or inaccurate
             in red marrow. Method The technique evaluated in this study
             measures the evolution frequency of intermolecular zero
             quantum coherences (iZQCs) between fat and water. The iZQC
             evolution frequency was mapped linearly to temperature. The
             temperature accuracy and coherence lifetime of the iZQC
             method were evaluated against other thermometry methods that
             are based on localized spectroscopy and multiple gradient
             echo imaging. Results The temperature coefficient (α) was
             9.8 ± 0.7 ppb/°C with the iZQC method and 2 ± 7 ppb/°C
             with traditional localized spectroscopy. Conclusion Because
             the accuracy of thermometry is limited by the
             reproducibility of α between samples, iZQCs provide nearly
             a 10-fold accuracy improvement in red marrow (0.7 ppb/°C
             for iZQCs versus 7 ppb/°C for localized spectroscopy.) The
             iZQC technique in this study will for the first time allow
             accurate and quantitative thermal imaging of red marrow.
             Magn Reson Med, 2014.},
   Doi = {10.1002/mrm.25372},
   Key = {fds234280}
}

@article{fds328176,
   Author = {Robles, FE and Deb, S and Wilson, JW and Gainey, CS and Selim, MA and Mosca, PJ and Tyler, DS and Fischer, MC and Warren,
             WS},
   Title = {Pump-probe imaging of pigmented cutaneous melanoma primary
             lesions gives insight into metastatic potential},
   Journal = {Biomedical Optics Express},
   Volume = {6},
   Number = {9},
   Pages = {3631-3645},
   Year = {2015},
   Month = {January},
   url = {http://dx.doi.org/10.1364/BOE.6.00363},
   Abstract = {© 2015 Optical Society of America. Metastatic melanoma is
             associated with a poor prognosis, but no method reliably
             predicts which melanomas of a given stage will ultimately
             metastasize and which will not. While sentinel lymph node
             biopsy (SLNB) has emerged as the most powerful predictor of
             metastatic disease, the majority of people dying from
             metastatic melanoma still have a negative SLNB. Here we
             analyze pump-probe microscopy images of thin biopsy slides
             of primary melanomas to assess their metastatic potential.
             Pumpprobe microscopy reveals detailed chemical information
             of melanin with subcellular spatial resolution.
             Quantification of the molecular signatures without reference
             standards is achieved using a geometrical representation of
             principal component analysis. Melanin structure is analyzed
             in unison with the chemical information by applying
             principles of mathematical morphology. Results show that
             melanin in metastatic primary lesions ha s lower chemical
             diversity than non-metastatic primary lesions, and contains
             two distinct phenotypes that are indicative of aggressive
             disease. Further, the mathematical morphology analysis
             reveals melanin in metastatic primary lesions has a distinct
             “dusty” quality. Finally, a statistical analysis shows
             that the combination of the chemical information with
             spatial structures predicts metastatic potential with much
             better sensitivity than SLNB and high specificity,
             suggesting pump-probe microscopy can be an important tool to
             help predict the metastatic potential of
             melanomas.},
   Doi = {10.1364/BOE.6.00363},
   Key = {fds328176}
}

@article{fds234294,
   Author = {Theis, T and Truong, M and Coffey, AM and Chekmenev, EY and Warren,
             WS},
   Title = {LIGHT-SABRE enables efficient in-magnet catalytic
             hyperpolarization.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {248},
   Pages = {23-26},
   Year = {2014},
   Month = {November},
   ISSN = {1090-7807},
   url = {http://dx.doi.org/10.1016/j.jmr.2014.09.005},
   Abstract = {Nuclear spin hyperpolarization overcomes the sensitivity
             limitations of traditional NMR and MRI, but the most general
             method demonstrated to date (dynamic nuclear polarization)
             has significant limitations in scalability, cost, and
             complex apparatus design. As an alternative, signal
             amplification by reversible exchange (SABRE) of parahydrogen
             on transition metal catalysts can hyperpolarize a variety of
             substrates, but to date this scheme has required transfer of
             the sample to low magnetic field or very strong RF
             irradiation. Here we demonstrate "Low-Irradiation Generation
             of High Tesla-SABRE" (LIGHT-SABRE) which works with simple
             pulse sequences and low power deposition; it should be
             usable at any magnetic field and for hyperpolarization of
             many different nuclei. This approach could drastically
             reduce the cost and complexity of producing hyperpolarized
             molecules.},
   Doi = {10.1016/j.jmr.2014.09.005},
   Key = {fds234294}
}

@article{fds234292,
   Author = {Claytor, K and Theis, T and Feng, Y and Yu, J and Gooden, D and Warren,
             WS},
   Title = {Accessing long-lived disconnected spin-1/2 eigenstates
             through spins > 1/2.},
   Journal = {Journal of the American Chemical Society},
   Volume = {136},
   Number = {43},
   Pages = {15118-15121},
   Year = {2014},
   Month = {October},
   ISSN = {0002-7863},
   url = {http://dx.doi.org/10.1021/ja505792j},
   Abstract = {Pairs of chemically equivalent (or nearly equivalent)
             spin-1/2 nuclei have been shown to create disconnected
             eigenstates that are very long-lived compared with the
             lifetime of pure magnetization (T1). Here the classes of
             molecules known to have accessible long-lived states are
             extended to include those with chemically equivalent
             spin-1/2 nuclei accessed by coupling to nuclei with spin >
             1/2, in this case deuterium. At first, this appears
             surprising because the quadrupolar interactions present in
             nuclei with spin > 1/2 are known to cause fast relaxation.
             Yet it is shown that scalar couplings between deuterium and
             carbon can guide population into and out of long-lived
             states, i.e., those immune from the dominant relaxation
             mechanisms. This implies that it may be practical to
             consider compounds with (13)C pairs directly bound to
             deuterium (or even (14)N) as candidates for storage of
             polarization. In addition, experiments show that simple
             deuteration of molecules with (13)C pairs at their natural
             abundance is sufficient for successful lifetime
             measurements.},
   Doi = {10.1021/ja505792j},
   Key = {fds234292}
}

@article{fds234291,
   Author = {Park, JK and Fischer, MC and Susumu, K and Therien, MJ and Warren,
             WS},
   Title = {Femtosecond pulse train shaping improves two-photon excited
             fluorescence measurements.},
   Journal = {Optics Letters},
   Volume = {39},
   Number = {19},
   Pages = {5606-5609},
   Year = {2014},
   Month = {October},
   ISSN = {0146-9592},
   url = {http://dx.doi.org/10.1364/ol.39.005606},
   Abstract = {Measurements of two-photon absorption (TPA) cross sections
             are greatly confounded by even very weak linear absorption,
             for example from hot bands. In this case, the experimental
             power dependence of fluorescence from amplified and
             mode-locked laser systems can differ drastically, even if
             the peak intensity is adjusted to be the same in both cases.
             A simple pulse train shaping method suppresses linear
             contributions and extracts the nonlinear absorption cross
             section, demonstrated here for a meso-to-meso ethyne-bridged
             bis[(porphinato)zinc(II)] fluorophore (DD) at 800 nm. This
             approach permits reliable TPA cross-section measurement,
             even with standard modelocked lasers under conditions
             identical to that used for multiphoton microscopy.},
   Doi = {10.1364/ol.39.005606},
   Key = {fds234291}
}

@article{fds234293,
   Author = {Feng, Y and Theis, T and Wu, T-L and Claytor, K and Warren,
             WS},
   Title = {Long-lived polarization protected by symmetry.},
   Journal = {Journal of Chemical Physics},
   Volume = {141},
   Number = {13},
   Pages = {134307},
   Year = {2014},
   Month = {October},
   ISSN = {0021-9606},
   url = {http://dx.doi.org/10.1063/1.4896895},
   Abstract = {In this paper we elucidate, theoretically and
             experimentally, molecular motifs which permit Long-Lived
             Polarization Protected by Symmetry (LOLIPOPS). The basic
             assembly principle starts from a pair of chemically
             equivalent nuclei supporting a long-lived singlet state and
             is completed by coupling to additional pairs of spins.
             LOLIPOPS can be created in various sizes; here we review
             four-spin systems, introduce a group theory analysis of
             six-spin systems, and explore eight-spin systems by
             simulation. The focus is on AA'XnX'n spin systems, where
             typically the A spins are (15)N or (13)C and X spins are
             protons. We describe the symmetry of the accessed states, we
             detail the pulse sequences used to access these states, we
             quantify the fraction of polarization that can be stored as
             LOLIPOPS, we elucidate how to access the protected states
             from A or from X polarization and we examine the behavior of
             these spin systems upon introduction of a small chemical
             shift difference.},
   Doi = {10.1063/1.4896895},
   Key = {fds234293}
}

@article{fds234295,
   Author = {Robles, FE and Fischer, MC and Warren, WS},
   Title = {Femtosecond pulse shaping enables detection of optical
             Kerr-effect (OKE) dynamics for molecular
             imaging.},
   Journal = {Optics Letters},
   Volume = {39},
   Number = {16},
   Pages = {4788-4791},
   Year = {2014},
   Month = {August},
   ISSN = {0146-9592},
   url = {http://dx.doi.org/10.1364/ol.39.004788},
   Abstract = {We apply femtosecond pulse shaping to generate optical pulse
             trains that directly access a material's nonlinear
             refractive index (n2) and can thus determine time-resolved
             optical Kerr-effect (OKE) dynamics. Two types of static
             pulse trains are discussed: The first uses two identical
             fields delayed in time, plus a pump field at a different
             wavelength. Time-resolved OKE dynamics are retrieved by
             monitoring the phase of the interference pattern produced by
             the two identical fields in the Fourier-domain (FD) as a
             function of pump-probe-time-delay (where the probe is one of
             the two identical fields). The second pulse train uses three
             fields with equal time delays, but with the center field
             phase shifted by π/2. In this pulse scheme, changes on a
             sample's nonlinear refractive index produce a new frequency
             in the FD signal, which in turn yields background-free
             intensity changes in the conjugate (time) domain and
             provides superior signal-to-noise ratios. The demonstrated
             sensitivity improvements enable, for the first time to our
             knowledge, molecular imaging based on OKE
             dynamics.},
   Doi = {10.1364/ol.39.004788},
   Key = {fds234295}
}

@article{fds234299,
   Author = {Davis, RM and Warren, WS},
   Title = {Intermolecular zero quantum coherences enable accurate
             temperature imaging in red bone marrow.},
   Journal = {Magnetic Resonance in Medicine},
   Year = {2014},
   Month = {July},
   ISSN = {0740-3194},
   Abstract = {Red bone marrow metastases are common in breast and prostate
             cancer patients, but those metastases are currently
             incurable. Recent developments show that hyperthermia could
             be a successful treatment for bone metastasis, but
             thermometry remains difficult or inaccurate in red
             marrow.The technique evaluated in this study measures the
             evolution frequency of intermolecular zero quantum
             coherences (iZQCs) between fat and water. The iZQC evolution
             frequency was mapped linearly to temperature. The
             temperature accuracy and coherence lifetime of the iZQC
             method were evaluated against other thermometry methods that
             are based on localized spectroscopy and multiple gradient
             echo imaging.The temperature coefficient (α) was
             9.8 ± 0.7 ppb/°C with the iZQC method and 2 ± 7
             ppb/°C with traditional localized spectroscopy.Because the
             accuracy of thermometry is limited by the reproducibility of
             α between samples, iZQCs provide nearly a 10-fold accuracy
             improvement in red marrow (0.7 ppb/°C for iZQCs versus 7
             ppb/°C for localized spectroscopy.) The iZQC technique in
             this study will for the first time allow accurate and
             quantitative thermal imaging of red marrow. Magn Reson Med,
             2014. © 2014 Wiley Periodicals, Inc.},
   Key = {fds234299}
}

@article{fds234298,
   Author = {Simpson, MJ and Glass, KE and Wilson, JW and Wilby, PR and Simon, JD and Warren, WS},
   Title = {Correction to “Pump–Probe Microscopic Imaging of
             Jurassic-Aged Eumelanin”},
   Journal = {Journal of Physical Chemistry Letters},
   Volume = {5},
   Number = {6},
   Pages = {946-946},
   Year = {2014},
   Month = {March},
   ISSN = {1948-7185},
   url = {http://dx.doi.org/10.1021/jz500406n},
   Doi = {10.1021/jz500406n},
   Key = {fds234298}
}

@article{fds234335,
   Author = {Claytor, K and Theis, T and Feng, Y and Warren, W},
   Title = {Measuring long-lived 13C2 state lifetimes at natural
             abundance.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {239},
   Pages = {81-86},
   Year = {2014},
   Month = {February},
   ISSN = {1090-7807},
   url = {http://dx.doi.org/10.1016/j.jmr.2013.12.009},
   Abstract = {Long-lived disconnected eigenstates (for example, the
             singlet state in a system with two nearly equivalent
             carbons, or the singlet-singlet state in a system with two
             chemically equivalent carbons and two chemically equivalent
             hydrogens) hold the potential to drastically extend the
             lifetime of hyperpolarization in molecular tracers for in
             vivo magnetic resonance imaging (MRI). However, a
             first-principles calculation of the expected lifetime (and
             thus selection of potential imaging agents) is made very
             difficult because of the large variety of relevant intra-
             and intermolecular relaxation mechanisms. As a result, all
             previous measurements relied on costly and time consuming
             syntheses of (13)C labeled compounds. Here we show that it
             is possible to determine (13)C singlet state lifetimes by
             detecting the naturally abundant doubly-labeled species.
             This approach allows for rapid and low cost screening of
             potential molecular biomarkers bearing long-lived
             states.},
   Doi = {10.1016/j.jmr.2013.12.009},
   Key = {fds234335}
}

@article{fds234346,
   Author = {Simpson, MJ and Wilson, JW and Robles, FE and Dall, CP and Glass, K and Simon, JD and Warren, WS},
   Title = {Near-infrared excited state dynamics of melanins: the
             effects of iron content, photo-damage, chemical oxidation,
             and aggregate size.},
   Journal = {The Journal of Physical Chemistry Part A: Molecules,
             Spectroscopy, Kinetics, Environment and General
             Theory},
   Volume = {118},
   Number = {6},
   Pages = {993-1003},
   Year = {2014},
   Month = {February},
   ISSN = {1089-5639},
   url = {http://dx.doi.org/10.1021/jp4107475},
   Abstract = {Ultrafast pump-probe measurements can discriminate the two
             forms of melanin found in biological tissue (eumelanin and
             pheomelanin), which may be useful for diagnosing and grading
             melanoma. However, recent work has shown that bound iron
             content changes eumelanin's pump-probe response, making it
             more similar to that of pheomelanin. Here we record the
             pump-probe response of these melanins at a wider range of
             wavelengths than previous work and show that with shorter
             pump wavelengths the response crosses over from being
             dominated by ground-state bleaching to being dominated by
             excited-state absorption. The crossover wavelength is
             different for each type of melanin. In our analysis, we
             found that the mechanism by which iron modifies eumelanin's
             pump-probe response cannot be attributed to Raman resonances
             or differences in melanin aggregation and is more likely
             caused by iron acting to broaden the unit spectra of
             individual chromophores in the heterogeneous melanin
             aggregate. We analyze the dependence on optical intensity,
             finding that iron-loaded eumelanin undergoes irreversible
             changes to the pump-probe response after intense laser
             exposure. Simultaneously acquired fluorescence data suggest
             that the previously reported "activation" of eumelanin
             fluorescence may be caused in part by the dissociation of
             metal ions or the selective degradation of iron-containing
             melanin.},
   Doi = {10.1021/jp4107475},
   Key = {fds234346}
}

@article{fds234348,
   Author = {Theis, T and Feng, Y and Wu, T and Warren, WS},
   Title = {Composite and shaped pulses for efficient and robust pumping
             of disconnected eigenstates in magnetic resonance.},
   Journal = {Journal of Chemical Physics},
   Volume = {140},
   Number = {1},
   Pages = {014201},
   Year = {2014},
   Month = {January},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/24410222},
   Abstract = {Hyperpolarization methods, which can enhance nuclear spin
             signals by orders of magnitude, open up important new
             opportunities in magnetic resonance. However, many of these
             applications are limited by spin lattice relaxation, which
             typically destroys the hyperpolarization in seconds.
             Significant lifetime enhancements have been found with
             "disconnected eigenstates" such as the singlet state between
             a pair of nearly equivalent spins, or the "singlet-singlet"
             state involving two pairs of chemically equivalent spins;
             the challenge is to populate these states (for example, from
             thermal equilibrium magnetization or hyperpolarization) and
             to later recall the population into observable signal.
             Existing methods for populating these states are limited by
             either excess energy dissipation or high sensitivity to
             inhomogeneities. Here we overcome the limitations by
             extending recent work using continuous-wave irradiation to
             include composite and adiabatic pulse excitations.
             Traditional composite and adiabatic pulses fail completely
             in this problem because the interactions driving the
             transitions are fundamentally different, but the new shapes
             we introduce can move population between accessible and
             disconnected eigenstates over a wide range of
             radio-frequency (RF) amplitudes and offsets while depositing
             insignificant amounts of power.},
   Doi = {10.1063/1.4851337},
   Key = {fds234348}
}

@article{fds234306,
   Author = {Robles, FE and Wilson, JW and Warren, WS},
   Title = {Quantifying melanin distribution using pump-probe microscopy
             and a 2D morphological autocorrelation transformation for
             melanoma diagnosis},
   Journal = {Proceedings of SPIE},
   Volume = {8949},
   Year = {2014},
   Month = {January},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.2038704},
   Abstract = {Pump-probe microscopy is a quantitative molecular imaging
             technique that yields diagnostically relevant information
             from endogenous pigments, like melanin, by probing their
             ultrafast photodynamic properties. Previously, the method
             was applied to image thin, pigmented, cutaneous samples at
             different stages of melanoma, and results have shown a
             correlation between melanin photodynamic behavior and
             malignancy. Here, we add to the diagnostic power of the
             method by applying principles of mathematical morphology to
             parameterize melanins' image structure. Along with bulk
             melanin chemical information, results show that this method
             can differentiate invasive melanomas from non-invasive and
             benign lesions with high sensitivity and specificity (92.3%
             and 97.5%, respectively, with N = 53). The mathematical
             method and the statistical analysis are described in detail
             and results from cutaneous and ocular conjuctival
             melanocytic lesions are presented. © 2014
             SPIE.},
   Doi = {10.1117/12.2038704},
   Key = {fds234306}
}

@article{fds234353,
   Author = {Robles, FE and Wilson, JW and Warren, WS},
   Title = {Quantifying melanin spatial distribution using pump-probe
             microscopy and a 2-D morphological autocorrelation
             transformation for melanoma diagnosis.},
   Journal = {Journal of Biomedical Optics},
   Volume = {18},
   Number = {12},
   Pages = {120502},
   Year = {2013},
   Month = {December},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/24296994},
   Abstract = {Pump-probe microscopy is an emerging molecular imaging
             technique that probes the excited state dynamics properties
             of pigmented samples. This method has been particularly
             intriguing for melanoma because, unlike other methods
             available, it can provide nondestructive, quantitative
             chemical information regarding different types of melanins,
             with high spatial resolution. In this Letter, we present a
             method based on mathematical morphology to quantify melanin
             structure (eumelanin, pheomelanin, and total melanin
             content, uniquely available with pump-probe microscopy) to
             aid in melanoma diagnosis. The approach applies a
             two-dimensional autocorrelation function and utilizes
             statistical parameters of the corresponding autocorrelation
             images, specifically, the second moments and entropy, to
             parameterize image structure. Along with bulk melanin
             chemical information, we show that this method can
             differentiate invasive melanomas from noninvasive and benign
             lesions with high sensitivity and specificity (92.3% and
             97.5%, respectively, with N=53). The mathematical method and
             the statistical analysis are described in detail and results
             from cutaneous and ocular conjunctival melanocytic lesions
             are presented.},
   Doi = {10.1117/1.JBO.18.12.120502},
   Key = {fds234353}
}

@article{fds234355,
   Author = {Wilson, JW and Vajzovic, L and Robles, FE and Cummings, TJ and Mruthyunjaya, P and Warren, WS},
   Title = {Imaging microscopic pigment chemistry in conjunctival
             melanocytic lesions using pump-probe laser
             microscopy.},
   Journal = {Investigative Ophthalmology and Visual Science},
   Volume = {54},
   Number = {10},
   Pages = {6867-6876},
   Year = {2013},
   Month = {October},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/24065811},
   Abstract = {PURPOSE: To report the application of a novel imaging
             technique, pump-probe microscopy, to analyze patterns of
             pigment chemistry of conjunctival melanocytic lesion
             biopsies. METHODS: Histopathologic specimens of eight
             previously excised conjunctival melanocytic lesions were
             analyzed with pump-probe microscopy. The technique uses a
             laser scanning microscope with a two-color pulsed laser
             source to distinguish hemoglobin, eumelanin, and pheomelanin
             pigment based on differences in transient excited state and
             ground state photodynamics. The pump-probe signatures of
             conjunctival melanins were compared with cutaneous melanins.
             The distributions of hemoglobin, eumelanin, and pheomelanin
             were analyzed, and pump-probe images were correlated with
             adjacent hematoxylin and eosin (H&E)-stained sections.
             RESULTS: The pump-probe signatures of conjunctival melanins
             are similar, but not identical to cutaneous melanins. In
             addition, there are qualitative and quantitative differences
             in the structure and pigment chemistry of conjunctival
             benign nevi, primary acquired melanosis of the conjunctiva
             (PAM), and conjunctival melanomas. The pump-probe images
             correlated well with histopathologic features observed in
             the adjacent H&E-stained sections, and provided a label-free
             means of discerning conjunctival anatomic features and
             pathologic benign or malignant tissue. CONCLUSIONS:
             Pump-probe laser microscopy shows promise as an adjuvant
             diagnostic tool in evaluation of ocular melanocytic lesions
             based on morphologic correlation with the histopathology
             results and pigment chemistry. This initial study suggests
             systematic differences in pigmentation patterns among
             conjunctival benign nevi, primary acquired melanosis, and
             melanomas. In addition, pump-probe microscopy has the
             potential for use as a noninvasive "in vivo" optical biopsy
             technique to aid clinical and surgical management of
             conjunctival melanocytic lesions.},
   Doi = {10.1167/iovs.13-12432},
   Key = {fds234355}
}

@article{fds234361,
   Author = {Feng, Y and Theis, T and Liang, X and Wang, Q and Zhou, P and Warren,
             WS},
   Title = {Storage of hydrogen spin polarization in long-lived 13C2
             singlet order and implications for hyperpolarized magnetic
             resonance imaging.},
   Journal = {Journal of the American Chemical Society},
   Volume = {135},
   Number = {26},
   Pages = {9632-9635},
   Year = {2013},
   Month = {July},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/23781874},
   Abstract = {Hyperpolarized magnetic resonance imaging (MRI) is a
             powerful technique enabling real-time monitoring of
             metabolites at concentration levels not accessible by
             standard MRI techniques. A considerable challenge this
             technique faces is the T1 decay of the hyperpolarization
             upon injection into the system under study. Here we show
             that A(n)A'(n)XX' spin systems such as (13)C2-1,2-diphenylacetylene
             ((13)C2-DPA) sustain long-lived polarization for both (13)C
             and (1)H spins with decay constants of almost 4.5 min at
             high magnetic fields of up to 16.44 T without spin-locking;
             the T1 of proton polarization is only 3.8 s. Therefore,
             storage of the proton polarization in a (13)C2-singlet state
             causes a 69-fold extension of the spin lifetime. Notably,
             this extension is demonstrated with proton-only pulse
             sequences, which can be readily implemented on standard
             clinical scanners.},
   Doi = {10.1021/ja404936p},
   Key = {fds234361}
}

@article{fds234359,
   Author = {Simpson, MJ and Glass, KE and Wilson, JW and Wilby, PR and Simon, JD and Warren, WS},
   Title = {Pump-Probe Microscopic Imaging of Jurassic-Aged
             Eumelanin.},
   Journal = {Journal of Physical Chemistry Letters},
   Volume = {4},
   Number = {11},
   Pages = {1924-1927},
   Year = {2013},
   Month = {June},
   ISSN = {1948-7185},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/23847720},
   Abstract = {Melanins are biological pigments found throughout the animal
             kingdom that have many diverse functions. Pump-probe imaging
             can differentiate the two kinds of melanins found in human
             skin, eumelanin and pheomelanin, the distributions of which
             are relevant to the diagnosis of melanoma. The long-term
             stability of the melanin pump-probe signal is central to
             using this technology to analyze melanin distributions in
             archived tissue samples to improve diagnostic procedures.
             This report shows that most of the pump-probe signal from
             eumelanin derived from a Jurassic cephalopod is essentially
             identical to that of eumelanin extracted from its modern
             counterpart, Sepia officinalis. However, additional classes
             of eumelanin signals found in the fossil reveal that the
             pump-probe signature is sensitive to iron content, which
             could be a valuable tool for pathologists who cannot
             otherwise know the microscopic distributions of iron in
             melanins.},
   Doi = {10.1021/jz4008036},
   Key = {fds234359}
}

@article{fds234362,
   Author = {Robles, FE and Samineni, P and Wilson, JW and Warren,
             WS},
   Title = {Pump-probe nonlinear phase dispersion spectroscopy},
   Journal = {Optics express},
   Volume = {21},
   Number = {8},
   Pages = {9353-9364},
   Year = {2013},
   Month = {April},
   ISSN = {1094-4087},
   url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000318151600017&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92},
   Abstract = {Pump-probe microscopy is an imaging technique that delivers
             molecular contrast of pigmented samples. Here, we introduce
             pump-probe nonlinear phase dispersion spectroscopy
             (PP-NLDS), a method that leverages pump-probe microscopy and
             spectral-domain interferometry to ascertain information from
             dispersive and resonant nonlinear effects. PP-NLDS extends
             the information content to four dimensions (phase,
             amplitude, wavelength, and pump-probe time-delay) that yield
             unique insight into a wider range of nonlinear interactions
             compared to conventional methods. This results in the
             ability to provide highly specific molecular contrast of
             pigmented and non-pigmented samples. A theoretical framework
             is described, and experimental results and simulations
             illustrate the potential of this method. Implications for
             biomedical imaging are discussed.},
   Doi = {10.1364/OE.21.009353},
   Key = {fds234362}
}

@article{fds234498,
   Author = {Stokes, AM and Feng, Y and Mitropoulos, T and Warren,
             WS},
   Title = {Enhanced refocusing of fat signals using optimized
             multipulse echo sequences.},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {69},
   Number = {4},
   Pages = {1044-1055},
   Year = {2013},
   Month = {April},
   ISSN = {0740-3194},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/22627966},
   Abstract = {Endogenous magnetic resonance contrast based on the
             localized composition of fat in vivo can provide functional
             information. We found that the unequal pulse timings of the
             Uhrig's dynamical decoupling multipulse echo sequences
             significantly alter the signal intensity compared to
             conventional, equal-spaced Carr-Purcell-Meiboom-Gill
             sequences. The signal increases and decreases depending on
             the tissue and sequence parameters, as well as on the
             interpulse spacings; particularly strong differences were
             observed in fatty tissues, which have a highly structured
             morphology and a wide range of chemical shifts and
             J-couplings. We found that the predominant mechanism for fat
             refocusing under multipulse echo sequences is the chemical
             structure, with stimulated echoes playing a pivotal role. As
             a result, specialized pulse sequences can be designed to
             optimize refocusing of the fat chemical shifts and
             J-couplings, where the degree of refocusing can be tailored
             to specific types of fats. To determine the optimal time
             delays, we simulated various Uhrig dynamical decoupling and
             Carr-Purcell-Meiboom-Gill pulse sequence timings, and these
             results are compared to experimental results obtained on
             excised and in vivo fatty tissue. Applications to
             intermolecular multiple quantum coherence imaging, where the
             improved echo refocusing translates directly into signal
             enhancements, are presented as well.},
   Doi = {10.1002/mrm.24340},
   Key = {fds234498}
}

@article{fds328179,
   Author = {Wilson, JW and Degan, S and Warren, WS and Fischer,
             MC},
   Title = {Optical clearing of archive-compatible paraffin embedded
             tissue for multiphoton microscopy (vol 3, pg 2752,
             2012)},
   Journal = {Biomedical Optics Express},
   Volume = {4},
   Number = {2},
   Pages = {219-219},
   Year = {2013},
   Month = {February},
   url = {http://dx.doi.org/10.1364/BOE.4.000219},
   Doi = {10.1364/BOE.4.000219},
   Key = {fds328179}
}

@article{fds234323,
   Author = {Robles, FE and Claytor, K and Warren, WS},
   Title = {Pump-probe nonlinear phase dispersion spectroscopy:
             Molecular contrast of pigmented and non-pigmented
             samples},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2013},
   Month = {January},
   Abstract = {Pump-probe nonlinear phase dispersion spectroscopy is a
             novel method that delivers molecular information of
             pigmented and non-pigmented samples by probing four
             dimensions: phase, amplitude, wavelength, and pump-probe
             time-delay. Its potential for molecular imaging is explored.
             © OSA 2013.},
   Key = {fds234323}
}

@article{fds222748,
   Author = {M.J. Simpson and J.W. Wilson and F.E. Robles and M.A. Selim and M.
             Phipps and W.S. Warren},
   Title = {Investigating the metastatic potential and pigment chemistry
             of melanomas using pump-probe imaging},
   Journal = {Proc. SPIE},
   Pages = {8565-3},
   Year = {2013},
   Key = {fds222748}
}

@article{fds222751,
   Author = {F.E. Robles and J.W. Wilson and M.C. Fischer and W.S.
             Warren},
   Title = {Phasor analysis for pump-probe microscopy},
   Journal = {Proc. SPIE},
   Pages = {8589-8},
   Year = {2013},
   Key = {fds222751}
}

@article{fds222758,
   Author = {J.W. Wilson and L. Vajzovic and F.E. Robles and T.J. Cummings and P.
             Mruthyunjaya and W.S. Warren},
   Title = {Imaging microscopic pigment chemistry in conjunctival
             lesions using pump-probe laser microscopy},
   Journal = {Invest. Ophthalmology Visual Science},
   Number = {54},
   Pages = {6867-6876},
   Year = {2013},
   Key = {fds222758}
}

@article{fds222759,
   Author = {F. E. Robles and J. W. Wilson and W. S. Warren},
   Title = {Quantifying melanin spatial distribution using pump-probe
             microscopy and a two-dimensional morphological
             autocorrelation transformation for melanoma
             diagnosis},
   Journal = {Journal of Biomedical Optics},
   Number = {18},
   Pages = {120502},
   Year = {2013},
   Key = {fds222759}
}

@article{fds234356,
   Author = {Wilson, JW and Degan, S and Fischer, MC and Warren,
             WS},
   Title = {Optical clearing and multiphoton imaging of
             paraffin-embedded specimens},
   Journal = {Proceedings of SPIE},
   Volume = {8588},
   Pages = {8588-40},
   Year = {2013},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.2003155},
   Abstract = {New labeling, imaging, or analysis tools could provide new
             retrospective insights when applied to archived,
             paraffinembedded samples. Deep-tissue multiphoton microscopy
             of paraffin-embedded specimens is achieved using optical
             clearing with mineral oil. We tested a variety of murine
             tissue specimens including skin, lung, spleen, kidney, and
             heart, acquiring multiphoton autofluorescence and
             second-harmonic generation, and pump-probe images This
             technique introduces the capability for non-destructive
             3-dimensional microscopic imaging of existing archived
             pathology specimens, enabling retrospective studies. © 2013
             SPIE.},
   Doi = {10.1117/12.2003155},
   Key = {fds234356}
}

@article{fds234357,
   Author = {Wilson, JW and Vajzovic, L and Robles, FE and Cummings, TJ and Mruthyunjaya, P and Warren, WS},
   Title = {Imaging pigment chemistry in melanocytic conjunctival
             lesions with pump-probe microscopy},
   Volume = {8567},
   Pages = {8567-18},
   Year = {2013},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.2003137},
   Abstract = {We extend nonlinear pump-probe microscopy, recently
             demonstrated to image the microscopic distribution of
             eumelanin and pheomelanin in unstained skin biopsy sections,
             to the case of melanocytic conjunctival lesions. The
             microscopic distribution of pigmentation chemistry serves as
             a functional indicator of melanocyte activity. In these
             conjunctival specimens (benign nevi, primary acquired
             melanoses, and conjunctival melanoma), we have observed
             pump-probe spectroscopic signatures of eumelanin,
             pheomelanin, hemoglobin, and surgical ink, in addition to
             important structural features that differentiate benign from
             malignant lesions. We will also discuss prospects for an in
             vivo 'optical biopsy' to provide additional information
             before having to perform invasive procedures. © 2013
             Copyright SPIE.},
   Doi = {10.1117/12.2003137},
   Key = {fds234357}
}

@article{fds234360,
   Author = {Robles, FE and Wilson, JW and Fischer, MC and Warren,
             WS},
   Title = {Adapting phasor analysis for nonlinear pump-probe
             microscopy},
   Journal = {Proceedings of SPIE},
   Volume = {8589},
   Year = {2013},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.2002600},
   Abstract = {Phasor analysis has become a powerful tool for examining
             signals in fluorescence life-time microscopy (FLIM), where
             the analysis provides a fast, robust and intuitive means of
             separating different fluorescent species and mixtures
             thereof. In this work we adapt this analysis for pump-probe
             microscopy, a method that provides molecular contrast of
             pigmented samples by probing their excited state dynamic
             properties. The bipolar nature of the pump-probe signals
             presents important differences in the resulting phasors
             compared to FLIM - here, we discuss these differences and
             describe the behavior of bipolar signals in phasor analysis.
             Results show that this method is indeed able to separate
             multiple molecular species of interests and allows facile
             assessment of pigment chemistry and its distribution in
             samples. © 2013 Copyright SPIE.},
   Doi = {10.1117/12.2002600},
   Key = {fds234360}
}

@article{fds234365,
   Author = {Simpson, MJ and Wilson, JW and Phipps, MA and Robles, FE and Selim, MA and Warren, WS},
   Title = {Nonlinear microscopy of eumelanin and pheomelanin with
             subcellular resolution},
   Journal = {Journal of Investigative Dermatology},
   Volume = {133},
   Number = {7},
   Pages = {1822-1826},
   Year = {2013},
   ISSN = {0022-202X},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/23353985},
   Abstract = {Pump-probe microscopy nondestructively differentiates
             eumelanin and pheomelanin and can be used to quantify
             melanin distributions in thin biopsy slices. Here we have
             extended that work for imaging eumelanin and pheomelanin
             distributions on a subcellular scale, allowing elucidation
             of characteristics of different cell types. The results show
             that melanin heterogeneity, previously found to be
             characteristic of melanomas, persists on the subcellular
             scale. We have also found spectral changes associated with
             melanin located in melanophages that could potentially
             differentiate invasive pigmented melanocytes from
             melanophages without immunohistochemical staining. © 2013
             The Society for Investigative Dermatology.},
   Doi = {10.1038/jid.2013.37},
   Key = {fds234365}
}

@article{fds318088,
   Author = {Stokes, AM and Feng, Y and Mitropoulos, T and Warren,
             WS},
   Title = {Enhanced refocusing of fat signals using optimized
             multipulse echo sequences},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {69},
   Number = {4},
   Pages = {1044-1055},
   Year = {2013},
   url = {http://dx.doi.org/10.1002/mrm.24340},
   Abstract = {Endogenous magnetic resonance contrast based on the
             localized composition of fat in vivo can provide functional
             information. We found that the unequal pulse timings of the
             Uhrig's dynamical decoupling multipulse echo sequences
             significantly alter the signal intensity compared to
             conventional, equal-spaced Carr-Purcell-Meiboom-Gill
             sequences. The signal increases and decreases depending on
             the tissue and sequence parameters, as well as on the
             interpulse spacings; particularly strong differences were
             observed in fatty tissues, which have a highly structured
             morphology and a wide range of chemical shifts and
             J-couplings. We found that the predominant mechanism for fat
             refocusing under multipulse echo sequences is the chemical
             structure, with stimulated echoes playing a pivotal role. As
             a result, specialized pulse sequences can be designed to
             optimize refocusing of the fat chemical shifts and
             J-couplings, where the degree of refocusing can be tailored
             to specific types of fats. To determine the optimal time
             delays, we simulated various Uhrig dynamical decoupling and
             Carr-Purcell-Meiboom-Gill pulse sequence timings, and these
             results are compared to experimental results obtained on
             excised and in vivo fatty tissue. Applications to
             intermolecular multiple quantum coherence imaging, where the
             improved echo refocusing translates directly into signal
             enhancements, are presented as well. © 2012 Wiley
             Periodicals, Inc.},
   Doi = {10.1002/mrm.24340},
   Key = {fds318088}
}

@article{fds234343,
   Author = {Villafaña, TE and Samineni, P and Warren, WS and Fischer,
             MC},
   Title = {Historical pigments revealed by pump-probe
             microscopy},
   Journal = {Laser Science, LS 2012},
   Year = {2012},
   Month = {December},
   Abstract = {Nonlinear optical pump-probe microscopy is able to
             sensitively extract excited state dynamics from historical
             art pigments. This technique allows three-dimensional
             imaging and characterization of different pigments, with far
             reaching applications for conservation science. © OSA
             2012.},
   Key = {fds234343}
}

@article{fds234344,
   Author = {Wilson, JW and Samineni, P and Fischer, MC and Warren,
             WS},
   Title = {Nonlinear cross-phase modulation microscopy using spectral
             shifting},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2012},
   Month = {December},
   Abstract = {Nonlinear phase contrast may be acquired by measuring
             spectral shifting of an ultrafast pulse due to cross phase
             modulation. This technique is used to obtain structural
             details in a pigmented cell from a melanoma biopsy. © OSA
             2012.},
   Key = {fds234344}
}

@article{fds234345,
   Author = {Simpson, MJ and Wilson, JW and Robles, FE and Phipps, T and Selim, MA and Warren, WS},
   Title = {Pump-probe imaging of melanin identifies metastatic
             potential of melanoma},
   Journal = {Frontiers in Optics, FIO 2012},
   Year = {2012},
   Month = {December},
   Abstract = {Two-color pump-probe microscopy produces chemical contrast
             between melanins in skin. Increased eumelanin fraction
             corresponds with worse melanoma prognosis. The spatial
             heterogeneity of the melanin fraction, both on a cellular
             and sub-cellular scale, also indicates malignancy. © OSA
             2012.},
   Key = {fds234345}
}

@article{fds234349,
   Author = {Samineni, P and DeCruz, A and Villafana, T and Fischer, MC and Warren,
             WS},
   Title = {Pump-probe microscopy of pigments used in historical
             art},
   Journal = {CLEO: Science and Innovations, CLEO_SI 2012},
   Pages = {CF1B.1},
   Year = {2012},
   Month = {December},
   Abstract = {We have developed a nonlinear microscopy technique that uses
             sensitive modulation transfer to extract excited state
             dynamics with high spatial resolution. Here, we use this
             technique to characterize several pigments used in
             historical artwork. © OSA 2012.},
   Key = {fds234349}
}

@article{fds234350,
   Author = {Wilson, JW and Samineni, P and Fischer, MC and Warren,
             WS},
   Title = {Nonlinear cross-phase modulation microscopy using spectral
             shifting},
   Journal = {CLEO: Science and Innovations, CLEO_SI 2012},
   Pages = {JW3G.2},
   Year = {2012},
   Month = {December},
   Abstract = {Nonlinear phase contrast may be acquired by measuring
             spectral shifting of an ultrafast pulse due to cross phase
             modulation. This technique is used to obtain structural
             details in a pigmented cell from a melanoma biopsy. © OSA
             2012.},
   Key = {fds234350}
}

@article{fds234351,
   Author = {Li, B and Yi, C and Brown, A and Fischer, MC and Warren,
             WS},
   Title = {Homodyne near-degenerate four-wave-mixing microscopy for
             graphene imaging and biomedical applications},
   Journal = {CLEO: Science and Innovations, CLEO_SI 2012},
   Pages = {CF1B.3},
   Year = {2012},
   Month = {December},
   Abstract = {Homodyne detection of near-degenerate four-wave-mixing with
             a single laser pulse is used to imaging graphene in
             biological samples. © OSA 2012.},
   Key = {fds234351}
}

@article{fds234352,
   Author = {Wilson, JW and Samineni, P and Fischer, MC and Warren,
             WS},
   Title = {Nonlinear cross-phase modulation microscopy using spectral
             shifting},
   Journal = {CLEO: Applications and Technology, CLEO_AT
             2012},
   Pages = {JW3G.2},
   Year = {2012},
   Month = {December},
   Abstract = {Nonlinear phase contrast may be acquired by measuring
             spectral shifting of an ultrafast ulse due to cross phase
             modulation. This technique is used to obtain structural
             details in a pigmented cell from a melanoma biopsy. © OSA
             2012.},
   Key = {fds234352}
}

@article{fds234532,
   Author = {Li, B and Cheng, Y and Liu, J and Yi, C and Brown, AS and Yuan, H and Vo-Dinh,
             T and Fischer, MC and Warren, WS},
   Title = {Direct optical imaging of graphene in vitro by nonlinear
             femtosecond laser spectral reshaping.},
   Journal = {Nano Letters},
   Volume = {12},
   Number = {11},
   Pages = {5936-5940},
   Year = {2012},
   Month = {November},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/23101475},
   Abstract = {Nonlinear optical microscopy, based on femtosecond laser
             spectral reshaping, characterized and imaged graphene
             samples made from different methods, both on slides and in a
             biological environment. This technique clearly discriminates
             between graphene flakes with different numbers of layers and
             reveals the distinct nonlinear optical properties of reduced
             graphene oxide as compared to mechanically exfoliated or
             chemical vapor deposition grown graphene. The nonlinearity
             makes it applicable to scattering samples (such as tissue)
             as opposed to previous methods, such as transmission. This
             was demonstrated by high-resolution imaging of breast cancer
             cells incubated with graphene flakes.},
   Doi = {10.1021/nl303358p},
   Key = {fds234532}
}

@article{fds234502,
   Author = {Feng, Y and Davis, RM and Warren, WS},
   Title = {Accessing long-lived nuclear singlet states between
             chemically equivalent spins without breaking
             symmetry.},
   Journal = {Nature Physics},
   Volume = {8},
   Number = {11},
   Pages = {831-837},
   Year = {2012},
   Month = {November},
   ISSN = {1745-2473},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/23505397},
   Abstract = {Long-lived nuclear spin states could greatly enhance the
             applicability of hyperpolarized nuclear magnetic resonance.
             Using singlet states between inequivalent spin pairs has
             been shown to extend the signal lifetime by more than an
             order of magnitude compared to the spin lattice relaxation
             time (T1), but they have to be prevented from evolving into
             other states. In the most interesting case the singlet is
             between chemically equivalent spins, as it can then be
             inherently an eigenstate. However this presents major
             challenges in the conversion from bulk magnetization to
             singlet. In the only case demonstrated so far, a reversible
             chemical reaction to break symmetry was required. Here we
             present a pulse sequence technique that interconverts
             between singlet spin order and bulk magnetization without
             breaking the symmetry of the spin system. This technique is
             independent of field strength and is applicable to a broad
             range of molecules.},
   Doi = {10.1038/nphys2425},
   Key = {fds234502}
}

@article{fds234527,
   Author = {Wilson, JW and Degan, S and Warren, WS and Fischer,
             MC},
   Title = {Optical clearing of archive-compatible paraffin embedded
             tissue for multiphoton microscopy.},
   Journal = {Biomedical Optics Express},
   Volume = {3},
   Number = {11},
   Pages = {2752-2760},
   Year = {2012},
   Month = {November},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/23162713},
   Abstract = {Standard histopathology techniques (including paraffin
             embedding) are incompatible with thick tissue multiphoton
             imaging, and standard clearing techniques on those specimens
             destroy some molecular information. We demonstrate
             multiphoton imaging in specimens prepared according to
             standard histopathology techniques. This permits unlabeled
             3-dimensional histology on archival tissue banks, which is
             of great value in evaluating prognostic indicators.},
   Doi = {10.1364/BOE.3.002752},
   Key = {fds234527}
}

@article{fds234501,
   Author = {Stokes, AM and Wilson, JW and Warren, WS},
   Title = {Characterization of restricted diffusion in uni- and
             multi-lamellar vesicles using short distance
             iMQCs.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {223},
   Pages = {31-40},
   Year = {2012},
   Month = {October},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/22975234},
   Abstract = {Improved understanding of the entrapment, transport, and
             release of drugs and small molecules within vesicles is
             important for drug delivery. Most methods rely on contrast
             agents or probe molecules; here, we propose a new MRI method
             to detect signal from water spins with restricted diffusion.
             This method is based on intermolecular double quantum
             coherences (iDQCs), which can probe the restricted diffusion
             characteristics at well-defined and tunable microscopic
             distance scales. By using an exceedingly short (and
             previously inaccessible) distance, the iDQC signal arises
             only from restricted diffusion spins and thereby provides a
             mechanism to directly image vesicle entrapment, transport,
             and release. Using uni- and multi-lamellar liposomes and
             polymersomes, we show how the composition, lamellar
             structure, vesicle size, and concentration affects the iDQC
             signal between coupled water spins at very short separation
             distances. The iDQC signal correlates well with conventional
             diffusion MRI and a proposed biexponential
             (multicompartmental) diffusion model. Finally, the iDQC
             signal was used to monitor dynamic changes in the lamellar
             structure as temperature-sensitive liposomes released their
             contents. These short distance iDQCs can probe the amount
             and diffusion of water entrapped in vesicles, which may be
             useful to further understand vesicle properties in materials
             science and drug delivery applications.},
   Doi = {10.1016/j.jmr.2012.07.021},
   Key = {fds234501}
}

@article{fds234525,
   Author = {Li, B and Claytor, KE and Yuan, H and Vo-Dinh, T and Warren, WS and Fischer, MC},
   Title = {Multicontrast nonlinear optical microscopy with a compact
             and rapid pulse shaper.},
   Journal = {Optics Letters},
   Volume = {37},
   Number = {13},
   Pages = {2763-2765},
   Year = {2012},
   Month = {July},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/22743521},
   Abstract = {Homodyne detection can dramatically enhance measurement
             sensitivity for weak signals. In nonlinear optical
             microscopy it can make accessible a range of novel,
             intrinsic, contrast like nonlinear absorption and nonlinear
             phase contrast. Here a compact and rapid pulse shaper is
             developed, implemented, and demonstrated for homodyne
             detection in nonlinear microscopy with high-repetition rate
             mode-locked femtosecond lasers. With this method we generate
             two-photon absorption (TPA) and self-phase modulation images
             of gold nanostars in biological samples. Simultaneous
             imaging of two-photon luminescence and TPA also enables us
             to produce two-photon quantum yield images.},
   Key = {fds234525}
}

@article{fds234500,
   Author = {Chen, YM and Branca, RT and Warren, WS},
   Title = {Revisiting the mean-field picture of dipolar effects in
             solution NMR.},
   Journal = {Journal of Chemical Physics},
   Volume = {136},
   Number = {20},
   Pages = {204509},
   Year = {2012},
   Month = {May},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/22667573},
   Abstract = {For more than three decades, the classical or mean-field
             picture describing the distant dipolar field has been almost
             always simplified to an effective field proportional to the
             local longitudinal magnetization, differing only by a scale
             factor of 1.5 for homomolecular (identical resonance
             frequency) and heteromolecular interactions. We re-examine
             the underlying assumptions, and show both theoretically and
             experimentally that the mathematical framework needs to be
             modified for modern applications such as imaging. We
             demonstrate new pulse sequences which produce unexpected
             effects; for example, modulating an arbitrarily small
             fraction of the magnetization can substantially alter the
             frequency evolution. Thus, matched gradient pulse pairs (a
             seemingly innocuous module in thousands of existing pulse
             sequences) can alter the time evolution in highly unexpected
             ways, particularly with small flip angle pulses such as
             those used in hyperpolarized experiments. We also show that
             specific gradient pulse combinations can retain only dipolar
             interactions between unlike spins, and the dipolar field can
             generate a secular Hamiltonian proportional to
             I(x).},
   Doi = {10.1063/1.4721637},
   Key = {fds234500}
}

@article{fds234523,
   Author = {Samineni, P and deCruz, A and Villafaña, TE and Warren, WS and Fischer,
             MC},
   Title = {Pump-probe imaging of historical pigments used in
             paintings.},
   Journal = {Optics Letters},
   Volume = {37},
   Number = {8},
   Pages = {1310-1312},
   Year = {2012},
   Month = {April},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/22513669},
   Abstract = {A recently developed nonlinear optical pump-probe microscopy
             technique uses modulation transfer to sensitively extract
             excited-state dynamics of endogenous biological pigments,
             such as eumelanin and pheomelanin. In this work, we use this
             method to image and characterize several inorganic and
             organic pigments used in historical art. We show substantial
             differences in the near-IR pump-probe signatures from
             nominally similar pigments and suggest extensions to art
             restoration.},
   Key = {fds234523}
}

@article{fds328180,
   Author = {Degan, S and Wilson, JW and Mitropoulos, TE and Zhang, JY and Selim, MA and Warren, WS},
   Title = {Abstract 381: Non-invasive histology for early detection of
             cutaneous melanoma and pigmented lesions in
             vivo},
   Journal = {Cancer Research},
   Volume = {72},
   Number = {8 Supplement},
   Pages = {381-381},
   Year = {2012},
   Month = {April},
   url = {http://dx.doi.org/10.1158/1538-7445.AM2012-381},
   Doi = {10.1158/1538-7445.AM2012-381},
   Key = {fds328180}
}

@article{fds234522,
   Author = {Samineni, P and Li, B and Wilson, JW and Warren, WS and Fischer,
             MC},
   Title = {Cross-phase modulation imaging.},
   Journal = {Optics Letters},
   Volume = {37},
   Number = {5},
   Pages = {800-802},
   Year = {2012},
   Month = {March},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/22378398},
   Abstract = {We demonstrate a cross-phase modulation measurement
             technique based on the sensitive detection of modulation
             transfer in a pump-probe setup. By modulating the amplitude
             of the pump beam and spectrally analyzing the probe beam, we
             achieve a rapid, background-free measurement of nonlinear
             phase modulation using power levels acceptable in biological
             imaging. This measurement technique would allow the
             extension of widely employed phase microscopy methods to the
             nonlinear regime, providing intrinsic and universal
             nonlinear contrast for biological imaging.},
   Key = {fds234522}
}

@article{fds234499,
   Author = {Cho, J-H and Hong, KS and Cho, J and Chang, S-K and Cheong, C and Lee, NH and Kim, H and Warren, WS and Ahn, S and Lee, C},
   Title = {Detection of iron-labeled single cells by MR imaging based
             on intermolecular double quantum coherences at 14
             T},
   Journal = {Journal of Magnetic Resonance},
   Volume = {217},
   Pages = {86-91},
   Year = {2012},
   ISSN = {1090-7807},
   url = {http://dx.doi.org/10.1016/j.jmr.2012.02.014},
   Abstract = {To evaluate the efficiency and feasibility of intermolecular
             multiple quantum coherence (iMQC) magnetic resonance (MR)
             imaging for single cell detection, we obtained
             intermolecular double quantum coherence (iDQC) and
             conventional gradient echo (GE) images of macrophage cells
             labeled by contrast agents in gel. The iDQC images obtained
             with echo-planar readout visualized the labeled cells
             effectively and with a higher contrast than seen in
             conventional GE images, especially at low planar resolutions
             and with thick slices. This implies that iDQC imaging with
             contrast agents could be a good alternative to conventional
             MR imaging for detecting labeled single cells or cell
             tracking under favorable conditions. © 2012 Elsevier Inc.
             All rights reserved.},
   Doi = {10.1016/j.jmr.2012.02.014},
   Key = {fds234499}
}

@article{fds234504,
   Author = {Wilson, JW and Degan, S and Mitropoulos, T and Selim, MA and Zhang, JY and Warren, WS},
   Title = {In vivo pump-probe microscopy of melanoma and pigmented
             lesions},
   Journal = {Proceedings of SPIE},
   Volume = {8226},
   Year = {2012},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.908821},
   Abstract = {A growing number of dermatologists and pathologists are
             concerned that the rapidly rising incidence of melanoma
             reflects not a true 'epidemic' but an increasing tendency to
             overdiagnose pigmented lesions. Addressing this problem
             requires both a better understanding of early-stage melanoma
             and new diagnostic criteria based on more than just cellular
             morphology and architecture. Here we present a method for
             in-vivo optical microscopy that utilizes pump-probe
             spectroscopy to image the distribution of the two forms of
             melanin in skin: eumelanin and pheomelanin. Images are
             acquired in a scanning microscope with a sensitive
             modulation transfer technique by analyzing back-scattered
             probe light with a lock-in amplifier. Early-stage melanoma
             is studied in a human skin xenografted mouse model.
             Individual melanocytes have been observed, in addition to
             pigmented keratinocytes. Combining the pump-probe images
             simultaneously with other noninvasive laser microscopy
             methods (confocal reflectance, multiphoton autofluorescence,
             and second harmonic generation) allows visualization of the
             skin architecture, framing the functional pump-probe image
             in the context of the surrounding tissue morphology. It is
             found that pump-probe images of melanin can be acquired with
             low peak intensities, enabling wide field-of-view
             pigmentation surveys. Finally, we investigate the diagnostic
             potential of the additional chemical information available
             from pump-probe microscopy. © 2012 Copyright Society of
             Photo-Optical Instrumentation Engineers (SPIE).},
   Doi = {10.1117/12.908821},
   Key = {fds234504}
}

@article{fds234520,
   Author = {Samineni, P and Cruz, AD and Villafana, T and Fischer, MC and Warren,
             WS},
   Title = {Pump-probe microscopy of pigments used in historical
             art},
   Journal = {2012 Conference on Lasers and Electro-Optics, CLEO
             2012},
   Year = {2012},
   Abstract = {We have developed a nonlinear microscopy technique that uses
             sensitive modulation transfer to extract excited state
             dynamics with high spatial resolution. Here, we use this
             technique to characterize several pigments used in
             historical artwork. © 2012 OSA.},
   Key = {fds234520}
}

@article{fds234521,
   Author = {Wilson, JW and Samineni, P and Fischer, MC and Warren,
             WS},
   Title = {Nonlinear cross-phase modulation microscopy using spectral
             shifting},
   Journal = {2012 Conference on Lasers and Electro-Optics, CLEO
             2012},
   Year = {2012},
   Abstract = {Nonlinear phase contrast may be acquired by measuring
             spectral shifting of an ultrafast pulse due to cross phase
             modulation. This technique is used to obtain structural
             details in a pigmented cell from a melanoma biopsy. © 2012
             OSA.},
   Key = {fds234521}
}

@article{fds234524,
   Author = {Wilson, JW and Samineni, P and Warren, WS and Fischer,
             MC},
   Title = {Cross-phase modulation spectral shifting: Nonlinear phase
             contrast in a pump-probe microscope},
   Journal = {Biomedical Optics Express},
   Volume = {3},
   Number = {5},
   Pages = {854-862},
   Year = {2012},
   ISSN = {2156-7085},
   url = {http://dx.doi.org/10.1364/BOE.3.000854},
   Abstract = {Microscopy with nonlinear phase contrast is achieved by a
             simple modification to a nonlinear pump-probe microscope.
             The technique measures cross-phase modulation by detecting a
             pump-induced spectral shift in the probe pulse. Images with
             nonlinear phase contrast are acquired both in transparent
             and absorptive media. In paraffin-embedded biopsy sections,
             cross-phase modulation complements the chemically-specific
             pump-probe images with structural context. © 2012 Optical
             Society of America.},
   Doi = {10.1364/BOE.3.000854},
   Key = {fds234524}
}

@article{fds234526,
   Author = {Robles, FE and Wilson, JW and Fischer, MC and Warren,
             WS},
   Title = {Phasor analysis for nonlinear pump-probe
             microscopy},
   Journal = {Optics express},
   Volume = {20},
   Number = {15},
   Pages = {17082-17092},
   Year = {2012},
   ISSN = {1094-4087},
   url = {http://dx.doi.org/10.1364/OE.20.017082},
   Abstract = {Pump-probe microscopy provides molecular information by
             probing transient, excited state dynamic properties of
             pigmented samples. Analysis of the transient response is
             typically conducted using principal component analysis or
             multi-exponential fitting, however these methods are not
             always practical or feasible. Here, we show an adaptation of
             phasor analysis to provide an intuitive, robust, and
             efficient method for analyzing and displaying pump-probe
             images, thereby alleviating some of the challenges
             associated with differentiating multiple pigments. A
             theoretical treatment is given to understand how the complex
             transient signals map onto the phasor plot. Analyses of
             cutaneous and ocular pigmented tissue samples, as well as
             historical pigments in art demonstrate the utility of this
             approach. ©2012 Optical Society of America.},
   Doi = {10.1364/OE.20.017082},
   Key = {fds234526}
}

@article{fds234531,
   Author = {Li, B and Yi, C and Brown, A and Fischer, MC and Warren,
             WS},
   Title = {Homodyne near-degenerate four-wave-mixing microscopy for
             graphene imaging and biomedical applications},
   Journal = {2012 Conference on Lasers and Electro-Optics, CLEO
             2012},
   Year = {2012},
   Abstract = {Homodyne detection of near-degenerate four-wave-mixing with
             a single laser pulse is used to imaging graphene in
             biological samples. © 2012 OSA.},
   Key = {fds234531}
}

@article{fds234597,
   Author = {Duarte, MF and Matthews, TE and Warren, WS and Calderbank,
             R},
   Title = {Melanoma classification from hidden Markov tree
             features},
   Journal = {IEEE International Conference on Acoustics Speech and Signal
             Processing},
   Pages = {685-688},
   Year = {2012},
   ISSN = {1520-6149},
   url = {http://dx.doi.org/10.1109/ICASSP.2012.6287976},
   Abstract = {Melanoma detection relies on visual inspection of skin
             samples under the microscope via a qualitative set of
             indicators, causing large discordance among pathologists.
             New developments in pump-probe imaging enable the extraction
             of melanin intensity levels from skin samples and provide
             baseline qualitative figures for melanoma detection and
             classification. However, such basic figures do not capture
             the diverse types of cellular structure that distinguish
             different stages of melanoma. In this paper, we propose an
             initial approach for feature extraction for classification
             purposes via Hidden Markov Tree models trained on skin
             sample melanin intensity images. Our experimental results
             show that the proposed features provide a mathematical
             microscope that is able to better discriminate cellular
             structure, enabling successful classification of skin
             samples that are mislabeled when the baseline melanin
             intensity qualitative figures are used. © 2012
             IEEE.},
   Doi = {10.1109/ICASSP.2012.6287976},
   Key = {fds234597}
}

@article{fds234317,
   Author = {Claytor, K and Li, B and Samineni, P and Warren, W and Fischer,
             M},
   Title = {Femtosecond pulse shaping enables nonlinear imaging in
             highly scattering materials},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Spectral re-shaping of pulses from a mode-locked femtosecond
             laser allows detection of two photon absorption and self
             phase modulation in highly scattering materials, which
             permits nonlinear tissue imaging with this intrinsic
             contrast. © 2011 OSA.},
   Key = {fds234317}
}

@article{fds234329,
   Author = {Wilson, JW and Warren, WS},
   Title = {Spectral shifting measurement of cross phase modulation with
             a balanced photodiode},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Biomedical imaging of the nonlinear refractive index n2
             requires a measurement technique that, unlike z-scan, is
             robust in inhomogeneous scattering media. We present an
             adaptation of a pump-probe experiment to measure n2 via
             cross-phase modulation. © 2011 OSA.},
   Key = {fds234329}
}

@article{fds234330,
   Author = {Warren, WS},
   Title = {Breasts and brains, similarities and differences: The role
             of nonlinear microscopy in molecular imaging},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {I will discuss the opportunities for nonlinear optical
             molecular imaging, focusing on measurement of intrinsic
             nonlinear optical signatures of cancer or of brain
             activation, and put this work in context with other
             modalities. © 2011 OSA.},
   Key = {fds234330}
}

@article{fds234331,
   Author = {Simpson, MJ and Wilson, JW and Matthews, TE and Duarte, M and Calderbank, R and Warren, WS},
   Title = {Imaging the distribution of melanin in human skin lesions
             with pump-probe microscopy},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Key = {fds234331}
}

@article{fds234332,
   Author = {Samineni, P and Fischer, MC and Warren, WS},
   Title = {Cross-phase modulation microscopy},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {We report our recently developed spectral re-shaping
             technique for cross-phase modulation imaging, which extends
             widely employed phase microscopy to the nonlinear regime. ©
             2011 OSA.},
   Key = {fds234332}
}

@article{fds234337,
   Author = {Wilson, JW and Matthews, TE and Degan, S and Zhang, JY and Simpson, MJ and Warren, WS},
   Title = {Pump-probe melanoma imaging: Applications to high-resolution
             and in-vivo microscopy},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Pump-probe imaging of melanin with near-infrared pulses has
             been extended to two new domains: high-resolution imaging of
             the melanin content of melanosomes in an individual
             melanocyte and epi-detected in vivo microscopy of a
             developing melanoma. © OSA/ CLEO 2011.},
   Key = {fds234337}
}

@article{fds234338,
   Author = {Wilson, JW and Matthews, TE and Degan, S and Zhang, JY and Simpson, MJ and Warren, WS},
   Title = {Pump-probe microscopy captures cellular detail of melanoma
             in-vivo.},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Pump-probe imaging of melanin with near-infrared pulses
             coupled with multphoton autofluorescence captures both
             chemical contrast and cellular detail in a live, developing
             melanoma. © 2011 OSA.},
   Key = {fds234338}
}

@article{fds234339,
   Author = {Wilson, JW and Matthews, TE and Degan, S and Zhang, JY and Simpson, MJ and Warren, WS},
   Title = {Pump-probe melanoma imaging: Applications to high-resolution
             and in-vivo microscopy},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Pump-probe imaging of melanin with near-infrared pulses has
             been extended to two new domains: high-resolution imaging of
             the melanin content of melanosomes in an individual
             melanocyte and epi-detected in vivo microscopy of a
             developing melanoma. © OSA/ CLEO 2011.},
   Key = {fds234339}
}

@article{fds234340,
   Author = {Fischer, MC and Samineni, P and Li, B and Claytor, K and Warren,
             WS},
   Title = {Accessing nonlinear phase contrast in biological tissue
             using femtosecond laser pulse shaping},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Nonlinear imaging takes advantage of the localized nature of
             the interaction to achieve high spatial resolution, optical
             sectioning, and deeper penetration in tissue. However,
             nonlinear contrast (other than fluorescence or harmonic
             generation) is generally difficult to measure because it is
             overwhelmed by the large background of detected illumination
             light. Especially challenging to measure is the nonlinear
             refractive index-accessing this quantity would allow the
             extension of widely employed phase microscopy methods to the
             nonlinear regime. We have developed a technique to suppress
             the background in these types of measurements by using
             femtosecond pulse shaping to encode nonlinear interactions
             in background-free regions of the frequency spectrum. Using
             this individual pulse shaping based technique we have been
             able to measure self-phase modulation (SPM) in highly
             scattering environments, such as biological tissue, with
             very modest power levels. Using our measurement technique we
             have demonstrated strong intrinsic SPM signatures of
             glutamate-induced neuronal activity in hippocampal brain
             slices. We have also extended this measurement method to
             cross-phase modulation, the two-color analogue to SPM. The
             two-color approach dramatically improves the measurement
             sensitivity by reducing undesired background and associated
             noise. We will describe the nonlinear phase contrast
             measurement technique and report on its application for
             imaging neuronal activity. © 2011 SPIE-OSA.},
   Key = {fds234340}
}

@article{fds234341,
   Author = {Li, B and Claytor, K and Warren, WS and Fischer, MC},
   Title = {Optimizing shape of femtosecond laser pulses for homodyne
             detection of nonlinear optical signals},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Based on homodyne detection of weak nonlinear signals with
             our spectral reshaping technique, pulse shapes are optimized
             for fast nonlinear imaging using femtosecond mode-locked
             lasers. © 2011 OSA.},
   Key = {fds234341}
}

@article{fds234342,
   Author = {Wilson, JW and Matthews, TE and Degan, S and Zhang, JY and Simpson, MJ and Warren, WS},
   Title = {Pump-probe melanoma imaging: Applications to high-resolution
             and in-vivo microscopy},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   Month = {December},
   Abstract = {Pump-probe imaging of melanin with near-infrared pulses has
             been extended to two new domains: high-resolution imaging of
             the melanin content of melanosomes in an individual
             melanocyte and epi-detected in vivo microscopy of a
             developing melanoma. © OSA/ CLEO 2011.},
   Key = {fds234342}
}

@article{fds234496,
   Author = {Branca, RT and Jenista, ER and Warren, WS},
   Title = {Inhomogeneity-free heteronuclear iMQC.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {209},
   Number = {2},
   Pages = {347-351},
   Year = {2011},
   Month = {April},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/21316278},
   Abstract = {Intermolecular dipolar interactions between proton and
             carbon spins can be used to indirectly detect carbon spectra
             with high sensitivity. In this communication, we present a
             modified sequence that, in addition to the high sensitivity
             of heteronuclear intermolecular multiple quantum coherence
             (iMQC) experiments, retains the line narrowing capability
             characteristic of homonuclear zero-quantum coherences. We
             demonstrate that this sequence can be used to obtain high
             resolution (13)C spectra in the presence of magnetic field
             inhomogeneities, both for thermal and hyperpolarized
             samples, and discuss applications to water-hyperpolarized
             carbon imaging.},
   Doi = {10.1016/j.jmr.2011.01.018},
   Key = {fds234496}
}

@article{fds234497,
   Author = {Branca, RT and Warren, WS},
   Title = {In vivo NMR detection of diet-induced changes in adipose
             tissue composition.},
   Journal = {Journal of lipid research},
   Volume = {52},
   Number = {4},
   Pages = {833-839},
   Year = {2011},
   Month = {April},
   ISSN = {0022-2275},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/21270099},
   Abstract = {We introduce an in vivo spectroscopic method to assess the
             effects of diet on fatty acid composition of the predominant
             chemical constituent of adipocytes in mice. To do this, we
             make use of a nonlinear NMR signal that, unlike a standard
             NMR signal, is intrinsically insensitive to local magnetic
             field inhomogeneities and which naturally suppresses the
             large water signal from nonfatty tissues. Our method yields
             fat composition information from fat depots distributed over
             large sample volumes in a single experiment, without
             requiring the use of tedious shimming procedures, voxel
             selection, or water suppression. Our results suggest that
             this method can reveal clear differences in adipose tissue
             composition of mice fed a standard chow diet compared with
             mice fed a diet rich in polyunsaturated fatty acids. With
             further developments this method could be used to obtain
             information on human lipid composition noninvasively and to
             track changes in lipid composition induced by diet
             intervention, pharmaceutical drugs, and exercise.},
   Doi = {10.1194/jlr.D012468},
   Key = {fds234497}
}

@article{fds328388,
   Author = {Warren, WS},
   Title = {Microscopy improves melanoma diagnosis},
   Journal = {Trends in Analytical Chemistry},
   Volume = {30},
   Number = {4},
   Pages = {VI-VII},
   Year = {2011},
   Month = {April},
   Key = {fds328388}
}

@article{fds234503,
   Author = {Matthews, TE and Piletic, IR and Selim, MA and Simpson, MJ and Warren,
             WS},
   Title = {Pump-probe imaging differentiates melanoma from melanocytic
             nevi.},
   Journal = {Science Translational Medicine},
   Volume = {3},
   Number = {71},
   Pages = {71ra15},
   Year = {2011},
   Month = {February},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/21346168},
   Abstract = {Melanoma diagnosis is clinically challenging: the accuracy
             of visual inspection by dermatologists is highly variable
             and heavily weighted toward false positives. Even the
             current gold standard of biopsy results in varying diagnoses
             among pathologists. We have developed a multiphoton
             technique (based on pump-probe spectroscopy) that directly
             determines the microscopic distribution of eumelanin and
             pheomelanin in pigmented lesions of human skin. Our initial
             results showed a marked difference in the chemical variety
             of melanin between nonmalignant nevi and melanoma, as well
             as a number of substantial architectural differences. We
             examined slices from 42 pigmented lesions and found that
             melanomas had an increased eumelanin content compared to
             nonmalignant nevi. When used as a diagnostic criterion, the
             ratio of eumelanin to pheomelanin captured all investigated
             melanomas but excluded three-quarters of dysplastic nevi and
             all benign dermal nevi. Additional evaluation of
             architectural and cytological features revealed by
             multiphoton imaging, including the maturation of
             melanocytes, presence of pigmented melanocytes in the
             dermis, number and location of melanocytic nests, and
             confluency of pigmented cells in the epidermis, further
             increased specificity, allowing rejection of more than half
             of the remaining false-positive results. We then adapted
             this multiphoton imaging technique to hematoxylin and eosin
             (H&E)-stained slides. By adding melanin chemical contrast to
             H&E-stained slides, pathologists will gain complementary
             information to increase the ease and accuracy of melanoma
             diagnosis.},
   Doi = {10.1126/scitranslmed.3001604},
   Key = {fds234503}
}

@article{fds234495,
   Author = {Branca, RT and Warren, WS},
   Title = {In vivo brown adipose tissue detection and characterization
             using water-lipid intermolecular zero-quantum
             coherences.},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {65},
   Number = {2},
   Pages = {313-319},
   Year = {2011},
   Month = {February},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/20939093},
   Abstract = {Brown adipose tissue and white adipose tissue depots are
             noninvasively characterized in vitro and in vivo in healthy
             and obese mice using intermolecular zero-quantum coherence
             transitions between lipid and water spins. Intermolecular
             zero-quantum coherences enable selective detection of
             spatial correlation between water and lipid spins and
             thereby the hydration of fatty deposits with subvoxel
             resolution. At about a 100 mm distance scale, the major
             observed peaks are between water, methylene protons at 1.3
             ppm, and olefinic protons at 5.3 ppm. Our in vitro results
             show that the methylene-olefinic intermolecular zero-quantum
             coherence signal is strong both in brown and white adipose
             tissues, but that the water-methylene intermolecular
             zero-quantum coherence signal is characteristic only of
             brown adipose tissue. In vivo, the ratio of these peaks is
             substantially higher in lean or young mice than in old or
             obese mice.},
   Doi = {10.1002/mrm.22622},
   Key = {fds234495}
}

@article{fds234327,
   Author = {Samineni, P and Fischer, MC and Liu, HC and Yasuda, R and Warren,
             WS},
   Title = {Nonlinear phase contrast imaging in neuronal
             tissue},
   Journal = {Optics InfoBase Conference Papers},
   Publisher = {Optical Society of America},
   Year = {2011},
   Abstract = {We demonstrate nonlinear phase contrast imaging in highly
             scattering media using rapid femtosecond pulse shaping of
             mode-locked laser pulses. We will also discuss potential
             applications of this technique for intrinsic functional
             neuronal imaging. © 2011 OSA: BODA/NTM/OMP/OTA.},
   Key = {fds234327}
}

@article{fds234328,
   Author = {Matthews, TE and Piletic, I and Selim, MA and Simpson, MJ and Warren,
             WS},
   Title = {Beyond Pathology: Pump-probe imaging of skin slices provides
             additional indicators of melanoma},
   Journal = {Optics InfoBase Conference Papers},
   Publisher = {Optical Society of America},
   Year = {2011},
   Abstract = {Principal component analysis of images taken with a
             pump-probe scanning microscope resolves eumelanin and
             pheomelanin. Utilizing intrinsic melanin contrast in skin
             slices has revealed significant differences between melanoma
             and other lesions. © 2011 OSA: BODA/NTM/OMP/OTA.},
   Key = {fds234328}
}

@article{fds234333,
   Author = {Matthews, TE and Piletic, I and Selim, MA and Simpson, MJ and Warren,
             WS},
   Title = {Beyond Pathology: Pump-probe imaging of skin slices provides
             additional indicators of melanoma},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   ISSN = {2162-2701},
   Key = {fds234333}
}

@article{fds234334,
   Author = {Samineni, P and Fischer, MC and Liu, HC and Yasuda, R and Warren,
             WS},
   Title = {Nonlinear phase contrast imaging in neuronal
             tissue},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2011},
   ISSN = {2162-2701},
   Key = {fds234334}
}

@article{fds234492,
   Author = {Matthews, TE and Wilson, JW and Degan, S and Simpson, MJ and Jin, JY and Zhang, JY and Warren, WS},
   Title = {In vivo and ex vivo epi-mode pump-probe imaging of melanin
             and microvasculature},
   Journal = {Biomedical Optics Express},
   Volume = {2},
   Number = {6},
   Pages = {1576-1583},
   Year = {2011},
   ISSN = {2156-7085},
   url = {http://dx.doi.org/10.1364/BOE.2.001576},
   Abstract = {We performed epi-mode pump-probe imaging of melanin in
             excised human pigmented lesions and both hemoglobin and
             melanin in live xenograft mouse melanoma models to depths
             greater than 100 μm. Eumelanin and pheomelanin images,
             which have been previously demonstrated to differentiate
             melanoma from benign lesions, were acquired at the
             dermal-epidermal junction with cellular resolution and
             modest optical powers (down to 15 mW). We imaged dermal
             microvasculature with the same wavelengths, allowing
             simultaneous acquisition of melanin, hemoglobin and
             multiphoton autofluorescence images. Molecular pump-probe
             imaging of melanocytes, skin structure and microvessels
             allows comprehensive, non-invasive characterization of
             pigmented lesions. © 2011 Optical Society of
             America.},
   Doi = {10.1364/BOE.2.001576},
   Key = {fds234492}
}

@article{fds234493,
   Author = {Wilson, JW and Matthews, TE and Degan, S and Zhang, JY and Simpson, MJ and Warren, WS},
   Title = {Pump-probe melanoma imaging: Applications to high-resolution
             and in-vivo microscopy},
   Journal = {2011 Conference on Lasers and Electro-Optics: Laser Science
             to Photonic Applications, CLEO 2011},
   Year = {2011},
   Abstract = {Pump-probe imaging of melanin with near-infrared pulses has
             been extended to two new domains: high-resolution imaging of
             the melanin content of melanosomes in an individual
             melanocyte and epi-detected in vivo microscopy of a
             developing melanoma. © 2011 OSA.},
   Key = {fds234493}
}

@article{fds234494,
   Author = {Kurhanewicz, J and Vigneron, DB and Brindle, K and Chekmenev, EY and Comment, A and Cunningham, CH and DeBerardinis, RJ and Green, GG and Leach, MO and Rajan, SS and Rizi, RR and Ross, BD and Warren, WS and Malloy, CR},
   Title = {Analysis of cancer metabolism by imaging hyperpolarized
             nuclei: Prospects for translation to clinical
             research},
   Journal = {Neoplasia (New York, N.Y.)},
   Volume = {13},
   Number = {2},
   Pages = {81-97},
   Year = {2011},
   ISSN = {1522-8002},
   url = {http://dx.doi.org/10.1593/neo.101102},
   Abstract = {A major challenge in cancer biology is to monitor and
             understand cancer metabolism in vivo with the goal of
             improved diagnosis and perhaps therapy. Because of the
             complexity of biochemical pathways, tracer methods are
             required for detecting specific enzyme-catalyzed reactions.
             Stable isotopes such as 13C or 15N with detection by nuclear
             magnetic resonance provide the necessary information about
             tissue biochemistry, but the crucial metabolites are present
             in low concentration and therefore are beyond the detection
             threshold of traditional magnetic resonance methods. A
             solution is to improve sensitivity by a factor of 10,000 or
             more by temporarily redistributing the populations of
             nuclear spins in a magnetic field, a process termed
             hyperpolarization. Although this effect is short-lived,
             hyperpolarized molecules can be generated in an aqueous
             solution and infused in vivo where metabolism generates
             products that can be imaged. This discovery lifts the
             primary constraint on magnetic resonance imaging for
             monitoring metabolism-poor sensitivity-while preserving the
             advantage of biochemical information. The purpose of this
             report was to briefly summarize the known abnormalities in
             cancer metabolism, the value and limitations of current
             imaging methods for metabolism, and the principles of
             hyperpolarization. Recent preclinical applications are
             described. Hyperpolarization technology is still in its
             infancy, and current polarizer equipment and methods are
             suboptimal. Nevertheless, there are no fundamental barriers
             to rapid translation of this exciting technology to clinical
             research and perhaps clinical care. © 2011 Neoplasia Press,
             Inc. All rights reserved.},
   Doi = {10.1593/neo.101102},
   Key = {fds234494}
}

@article{fds234519,
   Author = {Fischer, MC and Samineni, P and Li, B and Claytor, K and Warren,
             WS},
   Title = {Accessing nonlinear phase contrast in biological tissue
             using femtosecond laser pulse shaping},
   Journal = {Proceedings of SPIE},
   Volume = {8086},
   Year = {2011},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.889668},
   Abstract = {Nonlinear imaging takes advantage of the localized nature of
             the interaction to achieve high spatial resolution, optical
             sectioning, and deeper penetration in tissue. However,
             nonlinear contrast (other than fluorescence or harmonic
             generation) is generally difficult to measure because it is
             overwhelmed by the large background of detected illumination
             light. Especially challenging to measure is the nonlinear
             refractive index - accessing this quantity would allow the
             extension of widely employed phase microscopy methods to the
             nonlinear regime. We have developed a technique to suppress
             the background in these types of measurements by using
             femtosecond pulse shaping to encode nonlinear interactions
             in background-free regions of the frequency spectrum. Using
             this individual pulse shaping based technique we have been
             able to measure self-phase modulation (SPM) in highly
             scattering environments, such as biological tissue, with
             very modest power levels. Using our measurement technique we
             have demonstrated strong intrinsic SPM signatures of
             glutamate-induced neuronal activity in hippocampal brain
             slices. We have also extended this measurement method to
             cross-phase modulation, the two-color analogue to SPM. The
             two-color approach dramatically improves the measurement
             sensitivity by reducing undesired background and associated
             noise. We will describe the nonlinear phase contrast
             measurement technique and report on its application for
             imaging neuronal activity. © 2011 SPIE-OSA.},
   Doi = {10.1117/12.889668},
   Key = {fds234519}
}

@article{fds234518,
   Author = {Li, B and Warren, WS and Fischer, MC},
   Title = {Phase-cycling coherent anti-Stokes Raman scattering using
             shaped femtosecond laser pulses.},
   Journal = {Optics express},
   Volume = {18},
   Number = {25},
   Pages = {25825-25832},
   Year = {2010},
   Month = {December},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/21164927},
   Abstract = {We demonstrate a homodyne coherent anti-Stokes Raman
             scattering (CARS) technique based on femtosecond laser pulse
             shaping. This technique utilizes fast phase cycling to
             extract nonlinear Raman signatures with a self-generated
             reference signal acting as a local oscillator. The local
             oscillator is generated at the focus and is intrinsically
             stable relative to the Raman signal even in highly
             scattering samples. We can therefore retrieve phase
             information from the Raman signal and can suppress the
             ubiquitous non-resonant background.},
   Key = {fds234518}
}

@article{fds234324,
   Author = {Matthews, TE and Piletic, I and Selim, MA and Warren,
             WS},
   Title = {Nonlinear high-resolution imaging of eumelanin and
             pheomelanin distributions in normal skin tissue and
             melanoma},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2010},
   Month = {December},
   Abstract = {Two-color two-photon spectroscopy allows us for the first
             time to image the distribution of eumelanin and pheomelanin
             in tissue slices, giving histology-like detail and
             highlighting chemical and morphological changes in melanoma
             compared to benign lesions. © 2010 OSA/FiO/LS
             2010.},
   Key = {fds234324}
}

@article{fds234325,
   Author = {Samineni, P and Perret, Z and Warren, WS and Fischer,
             MC},
   Title = {Femtosecond laser pulse shaping improves self-phase
             modulation measurements in scattering media},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2010},
   Month = {December},
   Abstract = {We demonstrate that our recently developed spectral
             re-shaping technique improves the accuracy and precision of
             self-phase modulation measurements in scattering media over
             the conventional Z-scan method. © 2010 OSA/FiO/LS
             2010.},
   Key = {fds234325}
}

@article{fds234326,
   Author = {Li, B and Warren, WS and Fischer, MC},
   Title = {Enhancing coherent anti-stokes Raman scattering background
             suppression with phase cycled structured femtosecond laser
             pulses},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2010},
   Month = {December},
   Abstract = {We demonstrate a homodyne coherent anti-Stokes Raman
             scattering technique based on femtosecond laser pulse
             shaping (phase-cycling). This technique utilizes a
             self-generated non-resonant background as a local oscillator
             to retrieve phase information of the Raman signal. © 2010
             OSA/FiO/LS 2010.},
   Key = {fds234326}
}

@article{fds234491,
   Author = {Piletic, IR and Matthews, TE and Warren, WS},
   Title = {Probing near-infrared photorelaxation pathways in eumelanins
             and pheomelanins.},
   Journal = {The Journal of Physical Chemistry Part A: Molecules,
             Spectroscopy, Kinetics, Environment and General
             Theory},
   Volume = {114},
   Number = {43},
   Pages = {11483-11491},
   Year = {2010},
   Month = {November},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/20882951},
   Abstract = {Ultraviolet-visible spectroscopy readily discerns the two
             types of melanin pigments (eumelanin and pheomelanin),
             although fundamental details regarding the optical
             properties and pigment heterogeneity are more difficult to
             disentangle via analysis of the broad featureless absorption
             spectrum alone. We employed nonlinear transient absorption
             spectroscopy to study different melanin pigments at
             near-infrared wavelengths. Excited-state absorption,
             ground-state depletion, and stimulated emission signal
             contributions were distinguished for natural and synthetic
             eumelanins and pheomelanins. A starker contrast among the
             pigments is observed in the nonlinear excitation regime
             because they all exhibit distinct transient absorptive
             amplitudes, phase shifts, and nonexponential population
             dynamics spanning the femtosecond-nanosecond range. In this
             manner, different pigments within the pheomelanin subclass
             were distinguished in synthetic and human hair samples.
             These results highlight the potential of nonlinear
             spectroscopies to deliver an in situ analysis of natural
             melanins in tissue that are otherwise difficult to extract
             and purify.},
   Doi = {10.1021/jp103608d},
   Key = {fds234491}
}

@article{fds234517,
   Author = {Samineni, P and Perret, Z and Warren, WS and Fischer,
             MC},
   Title = {Measurements of nonlinear refractive index in scattering
             media.},
   Journal = {Optics express},
   Volume = {18},
   Number = {12},
   Pages = {12727-12735},
   Year = {2010},
   Month = {June},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/20588401},
   Abstract = {We have recently developed a spectral re-shaping technique
             to simultaneously measure nonlinear refractive index and
             nonlinear absorption. In this technique, the information
             about the nonlinearities is encoded in the frequency domain,
             rather than in the spatial domain as in the conventional
             Z-scan method. Here we show that frequency encoding is much
             more robust with respect to scattering. We compare spectral
             re-shaping and Z-scan measurements in a highly scattering
             environment and show that reliable spectral re-shaping
             measurements can be performed even in a regime that
             precludes standard Z-scans.},
   Key = {fds234517}
}

@article{fds234529,
   Author = {Jenista, ER and Galiana, G and Branca, RT and Yarmolenko, PS and Stokes,
             AM and Dewhirst, MW and Warren, WS},
   Title = {Application of mixed spin iMQCs for temperature and
             chemical-selective imaging.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {204},
   Number = {2},
   Pages = {208-218},
   Year = {2010},
   Month = {June},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/20303808},
   Abstract = {The development of accurate and non-invasive temperature
             imaging techniques has a wide variety of applications in
             fields such as medicine, chemistry and materials science.
             Accurate detection of temperature both in phantoms and in
             vivo can be obtained using iMQCs (intermolecular multiple
             quantum coherences), as demonstrated in a recent paper. This
             paper describes the underlying theory of iMQC temperature
             detection, as well as extensions of that work allowing not
             only for imaging of absolute temperature but also for
             imaging of analyte concentrations through
             chemically-selective spin density imaging.},
   Doi = {10.1016/j.jmr.2010.02.021},
   Key = {fds234529}
}

@article{fds234528,
   Author = {Branca, RT and Cleveland, ZI and Fubara, B and Kumar, CSSR and Maronpot,
             RR and Leuschner, C and Warren, WS and Driehuys, B},
   Title = {Molecular MRI for sensitive and specific detection of lung
             metastases.},
   Journal = {Proceedings of the National Academy of Sciences of
             USA},
   Volume = {107},
   Number = {8},
   Pages = {3693-3697},
   Year = {2010},
   Month = {February},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/20142483},
   Abstract = {Early and specific detection of metastatic cancer cells in
             the lung (the most common organ targeted by metastases)
             could significantly improve cancer treatment outcomes.
             However, the most widespread lung imaging methods use
             ionizing radiation and have low sensitivity and/or low
             specificity for cancer cells. Here we address this problem
             with an imaging method to detect submillimeter-sized
             metastases with molecular specificity. Cancer cells are
             targeted by iron oxide nanoparticles functionalized with
             cancer-binding ligands, then imaged by high-resolution
             hyperpolarized (3)He MRI. We demonstrate in vivo detection
             of pulmonary micrometastates in mice injected with breast
             adenocarcinoma cells. The method not only holds promise for
             cancer imaging but more generally suggests a fundamentally
             unique approach to molecular imaging in the
             lungs.},
   Doi = {10.1073/pnas.1000386107},
   Key = {fds234528}
}

@article{fds234490,
   Author = {Jenista, ER and Branca, RT and Warren, WS},
   Title = {Absolute temperature imaging using intermolecular multiple
             quantum MRI.},
   Journal = {International Journal of Hyperthermia (Informa)},
   Volume = {26},
   Number = {7},
   Pages = {725-734},
   Year = {2010},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/20849265},
   Abstract = {PURPOSE: A review of MRI temperature imaging methods based
             on intermolecular multiple quantum coherences (iMQCs) is
             presented. Temperature imaging based on iMQCs can provide
             absolute temperature maps that circumvent the artefacts that
             other proton frequency shift techniques suffer from such as
             distortions to the detected temperature due to
             susceptibility changes and magnetic field inhomogeneities.
             Thermometry based on iMQCs is promising in high-fat tissues
             such as the breast, since it relies on the fat signal as an
             internal reference. This review covers the theoretical
             background of iMQCs, and the necessary adaptations for
             temperature imaging using iMQCs. MATERIALS AND METHODS: Data
             is presented from several papers on iMQC temperature
             imaging. These studies were done at 7T in both phantoms and
             in vivo. Results from phantoms of cream (homogeneous mixture
             of water and fat) are presented as well as in vivo
             temperature maps in obese mice. RESULTS: Thermometry based
             on iMQCs offers the potential to provide temperature maps
             which are free of artefacts due to susceptibility and
             magnetic field inhomogeneities, and detect temperature on an
             absolute scale. CONCLUSIONS: The data presented in the
             papers reviewed highlights the promise of iMQC-based
             temperature imaging in fatty tissues such as the breast. The
             change in susceptibility of fat with temperature makes
             standard proton frequency shift methods (even with fat
             suppression) challenging and iMQC-based imaging offers an
             alternative approach.},
   Doi = {10.3109/02656736.2010.499527},
   Key = {fds234490}
}

@article{fds234307,
   Author = {Warren, WS and Piletic, I and Fischer, M and Fu, D and Samenini, P and Matthews, T},
   Title = {Nonlinear microscopy without fluorescence: Seeing the needle
             in the Haystack with Femtosecond pulse shaping},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2009},
   Month = {December},
   Key = {fds234307}
}

@article{fds234482,
   Author = {Jenista, ER and Stokes, AM and Branca, RT and Warren,
             WS},
   Title = {Optimized, unequal pulse spacing in multiple echo sequences
             improves refocusing in magnetic resonance.},
   Journal = {Journal of Chemical Physics},
   Volume = {131},
   Number = {20},
   Pages = {204510},
   Year = {2009},
   Month = {November},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/19947697},
   Abstract = {A recent quantum computing paper (G. S. Uhrig, Phys. Rev.
             Lett. 98, 100504 (2007)) analytically derived optimal pulse
             spacings for a multiple spin echo sequence designed to
             remove decoherence in a two-level system coupled to a bath.
             The spacings in what has been called a "Uhrig dynamic
             decoupling (UDD) sequence" differ dramatically from the
             conventional, equal pulse spacing of a Carr-Purcell-Meiboom-Gill
             (CPMG) multiple spin echo sequence. The UDD sequence was
             derived for a model that is unrelated to magnetic resonance,
             but was recently shown theoretically to be more general.
             Here we show that the UDD sequence has theoretical
             advantages for magnetic resonance imaging of structured
             materials such as tissue, where diffusion in
             compartmentalized and microstructured environments leads to
             fluctuating fields on a range of different time scales. We
             also show experimentally, both in excised tissue and in a
             live mouse tumor model, that optimal UDD sequences produce
             different T(2)-weighted contrast than do CPMG sequences with
             the same number of pulses and total delay, with substantial
             enhancements in most regions. This permits improved
             characterization of low-frequency spectral density functions
             in a wide range of applications.},
   Doi = {10.1063/1.3263196},
   Key = {fds234482}
}

@article{fds234483,
   Author = {Piletic, IR and Matthews, TE and Warren, WS},
   Title = {Estimation of molar absorptivities and pigment sizes for
             eumelanin and pheomelanin using femtosecond transient
             absorption spectroscopy.},
   Journal = {Journal of Chemical Physics},
   Volume = {131},
   Number = {18},
   Pages = {181106},
   Year = {2009},
   Month = {November},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/19916591},
   Abstract = {Fundamental optical and structural properties of melanins
             are not well understood due to their poor solubility
             characteristics and the chemical disorder present during
             biomolecular synthesis. We apply nonlinear transient
             absorption spectroscopy to quantify molar absorptivities for
             eumelanin and pheomelanin and thereby get an estimate for
             their average pigment sizes. We determine that pheomelanin
             exhibits a larger molar absorptivity at near IR wavelengths
             (750 nm), which may be extended to shorter wavelengths.
             Using the molar absorptivities, we estimate that melanin
             pigments contain approximately 46 and 28 monomer units for
             eumelanin and pheomelanin, respectively. This is
             considerably larger than the oligomeric species that have
             been recently proposed to account for the absorption
             spectrum of eumelanin and illustrates that larger pigments
             comprise a significant fraction of the pigment
             distribution.},
   Doi = {10.1063/1.3265861},
   Key = {fds234483}
}

@article{fds234488,
   Author = {Branca, RT and Chen, YM and Mouraviev, V and Galiana, G and Jenista, ER and Kumar, C and Leuschner, C and Warren, WS},
   Title = {iDQC anisotropy map imaging for tumor tissue
             characterization in vivo.},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {61},
   Number = {4},
   Pages = {937-943},
   Year = {2009},
   Month = {April},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/19215050},
   Abstract = {Intermolecular double quantum coherences (iDQCs), signals
             that result from simultaneous transitions of two or more
             separated spins, are known to produce images that are highly
             sensitive to subvoxel structure, particularly local
             anisotropy. Here we demonstrate how iDQCs signal can be used
             to efficiently detect the anisotropy created in breast tumor
             tissues and prostate tumor tissues by targeted
             (LHRH-conjugated) superparamagnetic nanoparticles (SPIONs),
             thereby distinguishing the necrotic area from the
             surrounding tumor tissue.},
   Doi = {10.1002/mrm.21925},
   Key = {fds234488}
}

@article{fds234486,
   Author = {Warren, WS and Jenista, E and Branca, RT and Chen,
             X},
   Title = {Increasing hyperpolarized spin lifetimes through true
             singlet eigenstates.},
   Journal = {Science},
   Volume = {323},
   Number = {5922},
   Pages = {1711-1714},
   Year = {2009},
   Month = {March},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/19325112},
   Abstract = {The sensitivity limitations for magnetic resonance imaging
             of organic molecules have recently been addressed by
             hyperpolarization methods, which prepare excess nuclear spin
             polarization. This approach can increase sensitivity by
             orders of magnitude, but the enhanced signal relaxes away in
             tens of seconds, even in favorable cases. Here we show
             theoretically that singlet states between strongly coupled
             spins in molecules can be used to store and retrieve
             population in very-long-lived disconnected eigenstates, as
             long as the coupling between the spins substantially exceeds
             both the couplings to other spins and the resonance
             frequency difference between them. Experimentally,
             2,3-carbon-13-labeled diacetyl has a disconnected eigenstate
             that can store population for minutes and is read out by
             hydration to make the two spins inequivalent.},
   Doi = {10.1126/science.1167693},
   Key = {fds234486}
}

@article{fds234481,
   Author = {Jenista, ER and Branca, RT and Warren, WS},
   Title = {Hyperpolarized carbon-carbon intermolecular multiple quantum
             coherences.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {196},
   Number = {1},
   Pages = {74-77},
   Year = {2009},
   Month = {January},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/18926750},
   Abstract = {Intermolecular multiple quantum coherences (iMQCs) can
             provide unique contrast with sub-voxel resolution. However,
             the characteristic growth rate of iMQCs mostly limits these
             effects to either hydrogen or hydrogen-coupled systems for
             thermally polarized samples. Hyperpolarization techniques
             such as dynamic nuclear polarization (DNP) allow for
             significant increases in the carbon signal (even more signal
             than that from hydrogen), making carbon iMQCs achievable. We
             present the first intermolecular multiple quantum signal
             between two carbon nuclei.},
   Doi = {10.1016/j.jmr.2008.09.027},
   Key = {fds234481}
}

@article{fds234484,
   Author = {Austin, RH and Xie, A and Fu, D and Warren, WW and Redlich, B and Meer,
             LVD},
   Title = {Tilting after dutch windmills: Probably no long-lived
             davydov solitons in proteins},
   Journal = {Journal of Biological Physics},
   Volume = {35},
   Number = {1},
   Pages = {91-101},
   Year = {2009},
   ISSN = {0092-0606},
   url = {http://dx.doi.org/10.1007/s10867-009-9130-7},
   Abstract = {We present a summary of picosecond pump-probe and photon
             echo experiments in the mid-IR at 6 μm on the protein
             myoglobin. The intriguing temperature dependence of the
             amide I band in Mb is rather similar to the temperature
             dependence of the amide I band of acetanilide, the molecule
             that launched Al Scott down the road of looking for Davydov
             solitons in biology. Alas, after much effort, we believe the
             data show that there is no long-lived Davydov soliton, at
             least in myoglobin. © 2009 Springer Science+Business Media
             B.V.},
   Doi = {10.1007/s10867-009-9130-7},
   Key = {fds234484}
}

@article{fds234485,
   Author = {Branca, RT and Warren, WS},
   Title = {Solvent suppression without crosspeak attenuation in iZQC
             experiments},
   Journal = {Chemical Physics Letters},
   Volume = {470},
   Number = {4-6},
   Pages = {325-331},
   Year = {2009},
   ISSN = {0009-2614},
   url = {http://dx.doi.org/10.1016/j.cplett.2009.01.063},
   Abstract = {The observation of solvent-solute iZQC peaks is often
             hampered by strong nearby solvent peaks. Previous
             researchers have overcome this problem by adding
             conventional solvent suppression modules during the dipolar
             evolution time. Here we show that these solvent suppression
             modules refocus the dipolar field and lead to a substantial
             signal intensity reduction, which is particularly damaging
             for the detection of low concentration species. We analyze,
             in detail, the effect of such modules on the signal
             formation, and demonstrate a method for solvent suppression
             that does not interfere with dipolar field evolution,
             leading to cleaner spectra. © 2009 Elsevier B.V. All rights
             reserved.},
   Doi = {10.1016/j.cplett.2009.01.063},
   Key = {fds234485}
}

@article{fds234487,
   Author = {Ye, T and Fu, D and Warren, WS},
   Title = {Nonlinear absorption microscopy},
   Journal = {Photochemistry & Photobiology},
   Volume = {85},
   Number = {3},
   Pages = {631-645},
   Year = {2009},
   ISSN = {0031-8655},
   url = {http://dx.doi.org/10.1111/j.1751-1097.2008.00514.x},
   Abstract = {For the past two decades, nonlinear microscopy has been
             developed to overcome the scattering problem in thick tissue
             imaging. Owing to its increased imaging depth and high
             spatial resolution, nonlinear microscopy becomes the first
             choice for imaging living tissues. The use of nonlinear
             optical effects not only facilitates the signal originating
             from an extremely small volume defined by light focusing but
             also provides novel contrast mechanisms with molecular
             specificity. Nonlinear absorption is a nonlinear optical
             effect in which the absorption coefficient depends on
             excitation intensity. As a commonly used spectroscopy tool,
             nonlinear absorption measurement uncovers many photophysical
             and photochemical processes correlated with electronic
             states of molecules. Recently we have been focusing on
             adapting this spectroscopy method to a microscopy imaging
             technique. The effort leads to a novel modality in nonlinear
             microscopy - nonlinear absorption microscopy. This article
             summarizes the principles and instrumentation of this
             imaging technique and highlights some of the recent progress
             in applying it to imaging skin pigmentation and
             microvasculature under ex vivo or in vivo conditions. ©
             2008 The American Society of Photobiology.},
   Doi = {10.1111/j.1751-1097.2008.00514.x},
   Key = {fds234487}
}

@article{fds234489,
   Author = {Meng, J and Fan, J and Galiana, G and Branca, RT and Clasen, PL and Ma, S and Zhou, J and Leuschner, C and Kumar, CSSR and Hormes, J and Otiti, T and Beye, AC and Harmer, MP and Kiely, CJ and Warren, W and Haataja, MP and Soboyejo, WO},
   Title = {LHRH-functionalized superparamagnetic iron oxide
             nanoparticles for breast cancer targeting and contrast
             enhancement in MRI},
   Journal = {Materials Science and Engineering: C},
   Volume = {29},
   Number = {4},
   Pages = {1467-1479},
   Year = {2009},
   ISSN = {0928-4931},
   url = {http://dx.doi.org/10.1016/j.msec.2008.09.039},
   Abstract = {This paper shows that superparamagnetic iron oxide
             nanoparticles (SPIONs) conjugated to luteinizing hormone
             releasing hormone (LHRH) (LHRH-SPIONs), can be used to
             target breast cancer cells. They also act as contrast
             enhancement agents during the magnetic resonance imaging of
             breast cancer xenografts. A combination of transmission
             electron microscopy (TEM) and spectrophotometric analysis
             was used in our experiments, to investigate the specific
             accumulation of the functionalized superparamagnetic iron
             oxide nanoparticles (SPIONs) in cancer cells. The contrast
             enhancement of conventional T2 images obtained from the
             tumor tissue and of breast cancer xenograft bearing mice is
             shown to be much greater than that in saline controls, when
             the tissues were injected with LHRH-SPIONs. Magnetic
             anisotropy multi-CRAZED images of tissues extracted from
             mice injected with SPIONs were also found to have enhanced
             MRI contrast in breast cancer xenografts and metastases in
             the lungs. © 2008.},
   Doi = {10.1016/j.msec.2008.09.039},
   Key = {fds234489}
}

@article{fds328181,
   Author = {Fischer, MC and Piletica, I and Fub, D and Matthewsa, TE and Liuc, H and Saminenia, P and Lid, B and Warrene, WS},
   Title = {Enhancing two-color absorption, self-phase modulation and
             raman microscopy signatures in tissue with femtosecond laser
             pulse shaping},
   Journal = {Proceedings of SPIE},
   Volume = {7183},
   Year = {2009},
   url = {http://dx.doi.org/10.1117/12.816488},
   Abstract = {Nonlinear microscopies (most commonly, two-photon
             fluorescence, second harmonic generation, and coherent
             anti-Stokes Raman scattering (CARS)) have had notable
             successes in imaging a variety of endogenous and exogenous
             targets in recent years. These methods generate light at a
             color different from any of the exciting laser pulses, which
             makes the signal relatively easy to detect. Our work has
             focused on developing microscopy techniques using a wider
             range of nonlinear signatures (two-photon absorption of
             nonfluorescent species, self phase modulation) which have
             some specific advantages - for example, in recent papers we
             have shown that we can differentiate between different types
             of melanin in pigmented lesions, image hemoglobin and its
             oxygenation, and measure neuronal activity. In general,
             these signatures do not generate light at a different color
             and we rely on the advantages of femtosecond laser pulse
             shaping methods to amplify the signals and make them visible
             (for example, using heterodyne detection of the induced
             signal with one of the co-propagating laser pulses). Here we
             extend this work to stimulated Raman and CARS geometries. In
             the simplest experiments, both colors arise from filtering a
             single fs laser pulse, then modulating afterwards; in other
             cases, we demonstrate that spectral reshaping can retain
             high frequency resolution in Raman and CARS geometries with
             femtosecond laser pulses. © 2009 SPIE.},
   Doi = {10.1117/12.816488},
   Key = {fds328181}
}

@article{fds234476,
   Author = {Branca, RT and Galiana, G and Warren, WS},
   Title = {Enhanced nonlinear magnetic resonance signals via square
             wave dipolar fields.},
   Journal = {Journal of Chemical Physics},
   Volume = {129},
   Number = {5},
   Pages = {054502},
   Year = {2008},
   Month = {August},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/18698909},
   Abstract = {This report introduces a new approach that enhances
             nonlinear solution magnetic resonance signals from
             intermolecular dipolar interactions. The resulting signals
             can theoretically be as large as the full equilibrium
             magnetization. Simple, readily implemented pulse sequences
             using square-wave magnetization modulation simultaneously
             refocus all even order intermolecular multiple quantum
             coherences, leading to a substantial net signal enhancement,
             complex nonlinear dynamics, and improved structural
             sensitivity under realistic conditions.},
   Doi = {10.1063/1.2962976},
   Key = {fds234476}
}

@article{fds234516,
   Author = {Piletic, IR and Fischer, MC and Samineni, P and Yurtsever, G and Warren,
             WS},
   Title = {Rapid pulse shaping with homodyne detection for measuring
             nonlinear optical signals.},
   Journal = {Optics Letters},
   Volume = {33},
   Number = {13},
   Pages = {1482-1484},
   Year = {2008},
   Month = {July},
   ISSN = {0146-9592},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/18594672},
   Abstract = {We have designed a common-mode interferometric acousto-optic
             pulse shaper that is capable of shaping individual pulses
             differently from a mode-locked laser. The design enables the
             measurement of weak nonlinear optical signals such as
             two-photon absorption and self-phase modulation at megahertz
             rates. The experimental apparatus incorporates homodyne
             detection as a means of resolving the phase of the detected
             signals. The fast data acquisition rate and the ability to
             perform measurements in scattering media make this
             experimental apparatus amenable to imaging applications
             analogous to measurements of two-photon fluorescence using a
             mode-locked laser.},
   Key = {fds234516}
}

@article{fds234515,
   Author = {Fischer, MC and Liu, HC and Piletic, IR and Warren,
             WS},
   Title = {Simultaneous self-phase modulation and two-photon absorption
             measurement by a spectral homodyne Z-scan
             method.},
   Journal = {Optics express},
   Volume = {16},
   Number = {6},
   Pages = {4192-4205},
   Year = {2008},
   Month = {March},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/18542515},
   Abstract = {We developed a technique to simultaneously measure
             self-phase modulation and two-photon absorption using shaped
             femtosecond laser pulses. In the conventional Z-scan
             measurement technique the amount of nonlinearity is
             determined by measuring the change in shape and intensity of
             a transmitted laser beam. In contrast, our method
             sensitively measures nonlinearity-induced changes in the
             pulse spectrum. In this work we demonstrate the technique in
             nonlinear absorptive and dispersive samples, quantify the
             obtained signal, and compare the measurements with
             traditional Z-scans. This technique is capable of measuring
             these nonlinearities in highly scattering
             samples.},
   Key = {fds234515}
}

@article{fds234514,
   Author = {Fischer, MC and Liu, HC and Piletic, IR and Escobedo-Lozoya, Y and Yasuda, R and Warren, WS},
   Title = {Self-phase modulation signatures of neuronal
             activity.},
   Journal = {Optics Letters},
   Volume = {33},
   Number = {3},
   Pages = {219-221},
   Year = {2008},
   Month = {February},
   ISSN = {0146-9592},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/18246134},
   Abstract = {We use phase-sensitive detection of spectral hole refilling
             to demonstrate strong novel intrinsic nonlinear signatures
             of neuronal activation in hippocampal brain slices. The
             ability to gain access to this fundamentally new intrinsic
             contrast with modest power levels suggests a new approach to
             in vivo neural imaging. We expect that we can extrapolate
             our method to high spatial and temporal resolution in deep
             tissue while retaining the noninvasive character.},
   Key = {fds234514}
}

@article{fds234316,
   Author = {Warren, WS and Fischer, M and Fu, D and Ye, T and Piletic, I and Matthews,
             T},
   Title = {New nonlinear signatures in spectroscopy and
             imaging},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2008},
   Month = {January},
   Abstract = {Ultrafast laser pulse shaping makes it possible to observe
             nonlinear signatures, such as self phase modulation and sum
             frequency absorption, at safe laser powers for tissue.
             Neuronal activation and melanoma diagnosis are two early
             targets. © 2008 Optical Society of America.},
   Key = {fds234316}
}

@article{fds234318,
   Author = {Fu, D and Warren, WS},
   Title = {Stimulated raman scattering with shaped ultrafast pulse
             trains},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2008},
   Month = {January},
   Abstract = {We explore the possibility of using Stimulated Raman (SRS)
             as a new imaging contrast and compared it to two photon
             absorption (TPA). Potential advantages over coherent
             anti-stokes Raman scattering (CARS) imaging are discussed.
             © 2008 Optical Society of America.},
   Key = {fds234318}
}

@article{fds234319,
   Author = {Liu, HC and Fischer, MC and Samineni, P and Escobedo-Lozoya, Y and Yasuda, R and Warren, WS},
   Title = {Intrinsic nonlinear optical signatures of neuronal
             activity},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2008},
   Month = {January},
   Abstract = {Using novel femtosecond laser pulse shaping techniques and a
             virtually background-free detection strategy we demonstrate
             strong self-phase modulation signatures of neuronal activity
             in hippocampal brain slices without the use of exogenous
             contrast agents. © 2008 Optical Society of
             America.},
   Key = {fds234319}
}

@article{fds234320,
   Author = {Fischer, MC and Liu, HC and Fu, D and Semineni, P and Matthews, T and Piletic, I and Warren, WS},
   Title = {Femtosecond laser pulse shaping for molecular imaging in
             biological tissue},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2008},
   Month = {January},
   Abstract = {Recently developed ultrafast laser pulse shaping technology
             allows highsensitivity measurements of nonlinear optical
             effects in highly scattering media. We present applications
             of these techniques to extract intrinsic structural,
             metabolic and functional contrast in biological tissue. ©
             2008 OSA.},
   Key = {fds234320}
}

@article{fds234321,
   Author = {Piletic, IR and Fischer, MC and Samineni, P and Warren,
             WS},
   Title = {Accessing nonlinear contrast in imaging using rapid pulse
             shaping techniques},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2008},
   Month = {January},
   Abstract = {We have designed an interferometric acousto-optic pulse
             shaper capable of shaping individual pulses differently from
             a mode-locked laser. The design enables the measurement of
             weak nonlinear optical signals at megahertz (MHz) rates for
             imaging applications. © 2008 Optical Society of
             America.},
   Key = {fds234321}
}

@article{fds234322,
   Author = {Warren, WS and Fischer, M and Fu, D and Ye, T and Piletic, I and Matthews,
             T},
   Title = {New nonlinear signatures in spectroscopy and
             imaging},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2008},
   Month = {January},
   Abstract = {Ultrafast laser pulse shaping makes it possible to observe
             nonlinear signatures, such as self phase modulation and sum
             frequency absorption, at safe laser powers for tissue.
             Neuronal activation and melanoma diagnosis are two early
             targets. ©2008 Optical Society of America.},
   Key = {fds234322}
}

@article{fds234474,
   Author = {Fu, D and Matthews, TE and Ye, T and Warren, WS},
   Title = {Label free high resolution in vivo optical imaging of
             microvessels},
   Journal = {Proceedings of SPIE},
   Volume = {6860},
   Year = {2008},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.763969},
   Abstract = {We have demonstrated a new optical microscopy technique for
             imaging microvasculature without any labeling. With a very
             sensitive two-color excited state absorption (ESA)
             measurement method, we demonstrated that oxy-hemoglobin and
             deoxy-hemoglobin show distinct excited state dynamics. Since
             this is a collinear measurement, we can readily apply it to
             the microscopic study of biological tissue. We have already
             demonstrated in vivo imaging of blood vessels in the nude
             mouse ear. Here we optimized the excitation and detection
             pulse train toward longer wavelengths, where tissue scatters
             less and greater penetration depth can be obtained. More
             importantly, we are able to separate arterioles from venules
             by employing different pump and probe wavelength
             combinations. This provides a powerful method to image blood
             vessels and their oxygenation level at the same time with
             micrometer resolution.},
   Doi = {10.1117/12.763969},
   Key = {fds234474}
}

@article{fds234475,
   Author = {Ye, T and Fu, D and Matthews, TE and Hong, L and Simon, JD and Warren,
             WS},
   Title = {Two-photon absorption and transient photothermal imaging of
             pigments in tissues},
   Journal = {Proceedings of SPIE},
   Volume = {6842},
   Year = {2008},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.764248},
   Abstract = {As a main pigment in skin tissues, melanin plays an
             important role in photo-protecting skin from UV radiation.
             However, melanogenesis may be altered due to disease or
             environmental factors; for example, sun exposure may cause
             damage and mutation of melanocytes and induce melanoma.
             Imaging pigmentation changes may provide invaluable
             information to catch the malignant transformation in its
             early stage and in turn improve the prognosis of patients.
             We have demonstrated previously that transmission mode,
             two-photon, one- or two-color absorption microscopy could
             provide remarkable contrast in imaging melanin in skin. In
             this report we demonstrate significantly improved
             sensitivity, so that we are now able to image in epi-mode
             (or back reflection) in two-photon absorption. This
             improvement makes possible for us to characterize the
             different types of pigmentation on the skin in vivo at
             virtually any location. Another finding is that we can also
             image transient photothermal dynamics due to the light
             absorption of melanin. By carefully choosing excitation and
             probe wavelengths, we might be able to image melanin in
             different structures under different micro-environments in
             skin, which could provide useful photochemical and
             photophysical insights in understanding how pigments are
             involved in photoprotection and photodamage of
             cells.},
   Doi = {10.1117/12.764248},
   Key = {fds234475}
}

@article{fds234477,
   Author = {Davis, JC and Fetterman, MR and Warren, WS and Goswami,
             D},
   Title = {Propagation of complex shaped ultrafast pulses in highly
             optically dense samples},
   Journal = {Journal of Chemical Physics},
   Volume = {128},
   Number = {15},
   Year = {2008},
   ISSN = {0021-9606},
   url = {http://dx.doi.org/10.1063/1.2894871},
   Abstract = {We examine the propagation of shaped (amplitude- and
             frequency-modulated) ultrafast laser pulses through
             optically dense rubidium vapor. Pulse reshaping, stimulated
             emission dynamics, and residual electronic excitation all
             strongly depend on the laser pulse shape. For example,
             frequency swept pulses, which produce adiabatic passage in
             the optically thin limit (independent of the sign of the
             frequency sweep), behave unexpectedly in optically dense
             samples. Paraxial Maxwell optical Bloch equations can model
             our ultrafast pulse propagation results well and provide
             insight. © 2008 American Institute of Physics.},
   Doi = {10.1063/1.2894871},
   Key = {fds234477}
}

@article{fds234478,
   Author = {Fu, D and Ye, T and Matthews, TE and Grichnik, J and Hong, L and Simon, JD and Warren, WS},
   Title = {Probing skin pigmentation changes with transient absorption
             imaging of eumelanin and pheomelanin},
   Journal = {Journal of Biomedical Optics},
   Volume = {13},
   Number = {5},
   Year = {2008},
   ISSN = {1083-3668},
   url = {http://dx.doi.org/10.1117/1.2976424},
   Abstract = {As some of the most ubiquitous and biologically important
             natural pigments, melanins play essential roles in the
             photoprotection of skin. Changes in melanin production could
             potentially be useful for clinical diagnosis of the
             progression stage of melanoma. Previously we demonstrated a
             new method for imaging melanin distribution in tissue with
             two-color transient absorption microscopy. Here we extend
             this study to longer wavelengths and show that we are able
             to image melanin in fixed thin skin slices with higher
             signal-to-noise ratios (SNRs) and demonstrate epimode
             imaging. We show that both photothermal effects and
             long-lived excited states can contribute to the long-lived
             signal. Eumelanin and pheomelanin exhibit markedly different
             long-lived excited state absorption. This difference should
             enable us to map out their respective distribution in tissue
             samples with subcellular resolution. This technique could
             provide valuable information in diagnosing the malignant
             transformation of melanocytes. © 2008 Society of
             Photo-Optical Instrumentation Engineers.},
   Doi = {10.1117/1.2976424},
   Key = {fds234478}
}

@article{fds234479,
   Author = {Fu, D and Matthews, TE and Ye, T and Piletic, IR and Warren,
             WS},
   Title = {Label-free in vivo optical imaging of microvasculature and
             oxygenation level},
   Journal = {Journal of Biomedical Optics},
   Volume = {13},
   Number = {4},
   Year = {2008},
   ISSN = {1083-3668},
   url = {http://dx.doi.org/10.1117/1.2968260},
   Abstract = {The ability to perform high-resolution imaging of
             microvasculature and its oxygenation is very important in
             studying early tumor development. Toward this goal, we
             improved upon our excited state absorption (ESA)-based
             imaging technique to allow us to not only image hemoglobin
             directly but also differentiate between oxy- and
             deoxyhemoglobin in tissue. We demonstrate the separation of
             arterioles from venules in a live nude mouse ear using our
             imaging technique. © 2008 Society of Photo-Optical
             Instrumentation Engineers.},
   Doi = {10.1117/1.2968260},
   Key = {fds234479}
}

@article{fds234480,
   Author = {Galiana, G and Branca, RT and Jenista, ER and Warren,
             WS},
   Title = {Accurate temperature imaging based on intermolecular
             coherences in magnetic resonance},
   Journal = {Science},
   Volume = {322},
   Number = {5900},
   Pages = {421-424},
   Year = {2008},
   ISSN = {0036-8075},
   url = {http://dx.doi.org/10.1126/science.1163242},
   Abstract = {Conventional magnetic resonance methods that provide
             interior temperature profiles, which find use in clinical
             applications such as hyperthermic therapy, can develop
             inaccuracies caused by the inherently inhomogeneous magnetic
             field within tissues or by probe dynamics, and work poorly
             in important applications such as fatty tissues. We present
             a magnetic resonance method that is suitable for imaging
             temperature in a wide range of environments. It uses the
             inherently sharp resonances of intermolecular zero-quantum
             coherences, in this case flipping up a water spin while
             flipping down a nearby fat spin. We show that this method
             can rapidly and accurately assign temperatures in vivo on an
             absolute scale.},
   Doi = {10.1126/science.1163242},
   Key = {fds234480}
}

@article{fds234512,
   Author = {Warren, WS and Fischer, M and Fu, D and Ye, T and Piletic, I and Matthews,
             T},
   Title = {New nonlinear signatures in spectroscopy and
             imaging},
   Journal = {Conference on Quantum Electronics and Laser Science (QELS) -
             Technical Digest Series},
   Year = {2008},
   url = {http://dx.doi.org/10.1109/QELS.2008.4552901},
   Abstract = {Ultrafast laser pulse shaping makes it possible to observe
             nonlinear signatures, such as self phase modulation and sum
             frequency absorption, at safe laser powers for tissue.
             Neuronal activation and melanoma diagnosis are two early
             targets. © 2008 Optical Society of America.},
   Doi = {10.1109/QELS.2008.4552901},
   Key = {fds234512}
}

@article{fds234513,
   Author = {Warren, WS and Fischer, M and Fu, D and Ye, T and Piletic, I and Matthews,
             T},
   Title = {New nonlinear signatures in spectroscopy and
             imaging},
   Journal = {2008 Conference on Quantum Electronics and Laser Science
             Conference on Lasers and Electro-Optics,
             CLEO/QELS},
   Year = {2008},
   url = {http://dx.doi.org/10.1109/CLEO.2008.4552392},
   Abstract = {Ultrafast laser pulse shaping makes it possible to observe
             nonlinear signatures, such as self phase modulation and sum
             frequency absorption, at safe laser powers for tissue.
             Neuronal activation and melanoma diagnosis are two early
             targets. © 2008 Optical Society of America.},
   Doi = {10.1109/CLEO.2008.4552392},
   Key = {fds234513}
}

@article{fds234473,
   Author = {Branca, RT and Galiana, G and Warren, WS},
   Title = {Signal enhancement in CRAZED experiments.},
   Journal = {Journal of Magnetic Resonance},
   Volume = {187},
   Number = {1},
   Pages = {38-43},
   Year = {2007},
   Month = {July},
   ISSN = {1090-7807},
   url = {http://www.ncbi.nlm.nih.gov/pubmed/17448714},
   Abstract = {Many of the promising applications of the CRAZED (COSY
             Revamped with Asymmetric Z-gradient Echo Detection)
             experiments are in biomedical and clinical technologies. In
             tissue, however, signal from the typical CRAZED experiment
             is largely limited by transverse relaxation. When relaxation
             is included, the maximum achievable signal from a
             prototypical CRAZED sequence, in the linear regime, is
             proportional to T(2)/tau(d). This means that for samples
             with a short T(2), as encountered in vivo, signals from
             intermolecular multiple-quantum coherences (iMQCs) reach
             very diminished signal intensities. While relaxation is
             generally regarded as a fundamental constraint, we show here
             that when T(2) is short but T(1) is long, as in tissue,
             there are simple sequence modifications that can increase
             signal beyond the T(2) limit. To better utilize the
             available signal intensity from iMQCs we propose a method to
             substitute part of the transverse magnetization with the
             longitudinally modulated magnetization. In this paper we
             show, with both simulations and experimental results, that
             in the presence of strong transverse relaxation the standard
             CRAZED scheme is not the optimal method for observing iMQCs,
             and can be improved upon with simple modifications.},
   Doi = {10.1016/j.jmr.2007.02.017},
   Key = {fds234473}
}

@article{fds234314,
   Author = {Fu, D and Matthews, TE and Ye, T and Yurtserver, G and Warren,
             WS},
   Title = {Two-photon absorption imaging of hemoglobin},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2007},
   Month = {January},
   Abstract = {We demonstrated that both oxyhemoglobin and deoxyhemoglobin
             has sequential twophoton absorption properties that can
             serve as endogenous contrasts in microvasculature imaging.
             They can also be differentiated through their different
             excited state dynamics. © 2007 Optical Society of
             America.},
   Key = {fds234314}
}

@article{fds234465,
   Author = {Leuschner, C and Kumar, C and Warren, W and Hansel, W and Branca, RT and Galiana, G and Hormes, F},
   Title = {Hormone peptide conjugated ironoxide nanoparticles for
             detection and treatment of metastases},
   Journal = {2007 NSTI Nanotechnology Conference and Trade Show - NSTI
             Nanotech 2007, Technical Proceedings},
   Volume = {2},
   Pages = {429-430},
   Year = {2007},
   Key = {fds234465}
}

@article{fds234466,
   Author = {Li, C and Wagner, W and Ciocca, M and Warren, WS},
   Title = {Multiphoton femtosecond phase-coherent two-dimensional
             electronic spectroscopy},
   Journal = {Journal of Chemical Physics},
   Volume = {126},
   Number = {16},
   Year = {2007},
   ISSN = {0021-9606},
   url = {http://dx.doi.org/10.1063/1.2721562},
   Abstract = {In this paper the authors compare 400 nm one-photon and 800
             nm two-photon two-dimensional Fourier transform electronic
             spectra of the organic laser dye Coumarin 102 in methanol
             using collinear optical pulse sequences and phase cycling.
             Results from the two different experiments show differences
             in the photon echo peak positions and shapes, reflecting
             differences in the two-photon and one-photon selection
             rules. © 2007 American Institute of Physics.},
   Doi = {10.1063/1.2721562},
   Key = {fds234466}
}

@article{fds234467,
   Author = {Fu, D and Ye, T and Matthews, TE and Yurtsever, G and Hong, L and Simon,
             JD and Warren, WS},
   Title = {Two-color excited-state absorption imaging of
             melanins},
   Journal = {Proceedings of SPIE},
   Volume = {6424},
   Year = {2007},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.698756},
   Abstract = {We have demonstrated a new method for imaging melanin with
             two-color excited state absorption microscopy. If one of two
             synchronized mode-locked pulse trains at different colors is
             intensity modulated, the modulation transfers to the other
             pulse train when nonlinear absorption takes place in the
             medium. We can easily measure 10-6 absorption changes caused
             by either instantaneous two-photon absorption or relatively
             long lived excited state absorption with a RF lock-in
             amplifier. Eumelanin and pheomelanin exhibit similar excited
             state dynamics. However, their difference in excited state
             absorption and ground state absorption leads to change in
             the phase of the transient absorption signal. Scanning
             microscopic imaging is performed with B16 cells, melanoma
             tissue to demonstrate the 3D high resolution imaging
             capability. Different melanosome samples are also imaged to
             illustrate the differences between eumelanin and pheomelanin
             signals. These differences could enable us to image their
             respective distribution in tissue samples and provide us
             with valuable information in diagnosing malignant
             transformation of melanocytes.},
   Doi = {10.1117/12.698756},
   Key = {fds234467}
}

@article{fds234468,
   Author = {Fu, D and Matthews, TE and Ye, T and Yurtserver, G and Warren,
             WS},
   Title = {Two-photon absorption imaging of hemoglobin},
   Journal = {Conference on Lasers and Electro-Optics, 2007, CLEO
             2007},
   Year = {2007},
   url = {http://dx.doi.org/10.1109/CLEO.2007.4452968},
   Abstract = {We demonstrated that both oxyhemoglobin and deoxyhemoglobin
             has sequential twophoton absorption properties that can
             serve as endogenous contrasts in microvasculature imaging.
             They can also be differentiated through their different
             excited state dynamics. © 2007 Optical Society of
             America.},
   Doi = {10.1109/CLEO.2007.4452968},
   Key = {fds234468}
}

@article{fds234469,
   Author = {Fu, D and Ye, T and Matthews, TE and Yurtsever, G and Warren,
             WS},
   Title = {Two-color, two-photon, and excited-state absorption
             microscopy},
   Journal = {Journal of Biomedical Optics},
   Volume = {12},
   Number = {5},
   Year = {2007},
   ISSN = {1083-3668},
   url = {http://dx.doi.org/10.1117/1.2780173},
   Abstract = {We develop a new approach in imaging nonfluorescent species
             with two-color two-photon and excited state absorption
             microscopy. If one of two synchronized mode-locked pulse
             trains at different colors is intensity modulated, the
             modulation transfers to the other pulse train when nonlinear
             absorption takes places in the medium. We can easily measure
             10-6 absorption changes caused by either two-photon
             absorption or excited-state absorption with a RF lock-in
             amplifier. Sepia melanin is studied in detail as a model
             system. Spectroscopy studies on the instantaneous two-photon
             absorption (TPA) and the relatively long-lived excited-state
             absorption (ESA) of melanin are carried out in solution, and
             imaging capability is demonstrated in B16 cells. It is found
             that sepia melanin exhibits two distinct excited states with
             different lifetimes (one at 3 ps, one lasting hundreds of
             nanoseconds) when pumped at 775 nm. Its characteristic
             TPA/ESA enables us to image its distribution in cell samples
             with high resolution comparable to two-photon fluorescence
             microscopy (TPFM). This new technique could potentially
             provide valuable information in diagnosing melanoma. © 2007
             Society of Photo-Optical Instrumentation
             Engineers.},
   Doi = {10.1117/1.2780173},
   Key = {fds234469}
}

@article{fds234470,
   Author = {Galiana, G and Branca, RT and Jenista, ER and Warren,
             WS},
   Title = {Intermolecular multiple quantum MR thermography},
   Journal = {Proceedings of the ASME Summer Bioengineering Conference
             2007, SBC 2007},
   Pages = {71-72},
   Year = {2007},
   Key = {fds234470}
}

@article{fds234471,
   Author = {Cho, J-H and Ahn, S and Lee, C and Hong, KS and Chung, K-C and Chang, S-K and Cheong, C and Warren, WS},
   Title = {Magnetic resonance microscopic imaging based on high-order
             intermolecular multiple-quantum coherences},
   Journal = {Magnetic Resonance Imaging},
   Volume = {25},
   Number = {5},
   Pages = {626-633},
   Year = {2007},
   ISSN = {0730-725X},
   url = {http://dx.doi.org/10.1016/j.mri.2006.09.005},
   Abstract = {Most imaging studies using intermolecular multiple-quantum
             coherences (iMQCs) have focused on the two-spin dipolar
             interactions - zero and double quantum coherences. Here, we
             report the results of various experimental studies to assess
             the feasibility of magnetic resonance microscopy with
             high-order iMQCs in model systems at 7 and 14 T.
             Experimental results demonstrated that the iMQC microscopic
             images with high coherence orders are readily observable at
             high field and have unique contrast depending on the sample
             microstructure and coherence order. © 2007.},
   Doi = {10.1016/j.mri.2006.09.005},
   Key = {fds234471}
}

@article{fds234472,
   Author = {Lisitza, NV and Warren, WS and Song, Y-Q},
   Title = {Study of diffusion in erythrocyte suspension using internal
             magnetic field inhomogeneity},
   Journal = {Journal of Magnetic Resonance},
   Volume = {187},
   Number = {1},
   Pages = {146-154},
   Year = {2007},
   ISSN = {1090-7807},
   url = {http://dx.doi.org/10.1016/j.jmr.2007.04.010},
   Abstract = {Transport of water and ions through cell membranes plays an
             important role in cell metabolism. We demonstrate a novel
             technique to measure water transport dynamics using
             erythrocyte suspensions as an example. This technique takes
             advantage of inhomogenous internal magnetic field created by
             the magnetic susceptibility contrast between the
             erythrocytes and plasma. The decay of longitudinal
             magnetization due to diffusion in this internal field
             reveals multi-exponential behavior, with one component
             corresponding to the diffusive exchange of water across
             erythrocyte membrane. The membrane permeability is obtained
             from the exchange time constant and is in good agreement
             with the literature values. As compared to the other
             methods, this technique does not require strong gradients of
             magnetic field or contrast agents and, potentially, can be
             applied in vivo. © 2007 Elsevier Inc. All rights
             reserved.},
   Doi = {10.1016/j.jmr.2007.04.010},
   Key = {fds234472}
}

@article{fds234510,
   Author = {Fischer, MC and Liu, H and Piletic, IR and Ye, T and Yasuda, R and Warren,
             WS},
   Title = {Self-phase modulation and two-photon absorption imaging of
             cells and active neurons},
   Journal = {Proceedings of SPIE},
   Volume = {6442},
   Year = {2007},
   ISSN = {1605-7422},
   url = {http://dx.doi.org/10.1117/12.698693},
   Abstract = {Even though multi-photon fluorescence microscopy offers
             higher resolution and better penetration depth than
             traditional fluorescence microscopy, its use is restricted
             to the detection of molecules that fluoresce. Two-photon
             absorption (TPA) imaging can provide contrast in
             non-fluorescent molecules while retaining the high
             resolution and sectioning capabilities of nonlinear imaging
             modalities. In the long-wavelength water window, tissue TPA
             is dominated by the endogenous molecules melanin and
             hemoglobin with an almost complete absence of endogenous
             two-photon fluorescence. A complementary nonlinear contrast
             mechanism is self-phase modulation (SPM), which can provide
             intrinsic signatures that can depend on local tissue
             anisotropy, chemical environment, or other structural
             properties. We have developed a spectral hole refilling
             measurement technique for TPA and SPM measurements using
             shaped ultrafast laser pulses. Here we report on a
             microscopy setup to simultaneously acquire 3D,
             high-resolution TPA and SPM images. We have acquired data in
             mounted B16 melanoma cells with very modest laser power
             levels. We will also discuss the possible application of
             this measurement technique to neuronal imaging. Since SPM is
             sensitive to material structure we can expect SPM properties
             of neurons to change during neuronal firing. Using our
             hole-refilling technique we have now demonstrated strong
             novel intrinsic nonlinear signatures of neuronal activation
             in a hippocampal brain slice. The observed changes in
             nonlinear signal upon collective activation were up to
             factors of two, unlike other intrinsic optical signal
             changes on the percent level. These results show that TPA
             and SPM imaging can provide important novel functional
             contrast in tissue using very modest power levels suitable
             for in vivo applications.},
   Doi = {10.1117/12.698693},
   Key = {fds234510}
}

@article{fds234511,
   Author = {Warren, WS and Fischer, MC and Tong, Y},
   Title = {Novel nonlinear contrast improves deep-tissue
             microscopy},
   Journal = {Laser Focus World},
   Volume = {43},
   Number = {6},
   Pages = {99-103},
   Year = {2007},
   ISSN = {1043-8092},
   Abstract = {Femtosecond laser pulse and pulse-train shaping allow
             detection of new nonlinear effects, with modest powers,
             making new biomarkers accessible and permitting deeper
             tissue imaging than conventional microscopy. The most
             developed of these technique create light at a new
             wavelength, which can then be separated from the exciting
             laser. While the two photon fluorescence (TPF) can be
             induced by continuous wave lasers, the vast majority of
             studies use short laser pulses to achieve high peak power
             with relatively low tissue damage from average power
             dissipation. Two photon absorption (TPA) and self-phase
             modulation (SPM) are the two most important
             single-wavelength effect for the purpose of tissue
             engineering. TPA is more effective on the intense pulses
             than on the weak ones, and it thus distorts the amplitude
             modulation, creating extra sidebands. Microscopic resolution
             to depths of about 1mm should be achievable in most tissues
             with far more physiological contrast than conventional
             microscopy.},
   Key = {fds234511}
}

@article{fds234530,
   Author = {Fu, D and Ye, T and Matthews, TE and Chen, BJ and Yurtserver, G and Warren,
             WS},
   Title = {High-resolution in vivo imaging of blood vessels without
             labeling},
   Journal = {Optics Letters},
   Volume = {32},
   Number = {18},
   Pages = {2641-2643},
   Year = {2007},
   ISSN = {0146-9592},
   url = {http://dx.doi.org/10.1364/OL.32.002641},
   Abstract = {We demonstrate that both oxyhemoglobin and deoxyhemoglobin
             have sequential two-color, two-photon absorption properties
             that can serve as endogenous contrasts in microvasculature
             imaging. Using a sensitive modulation transfer technique, we
             are able to image hemoglobin in red blood cells with
             micrometer resolution, both in vitro and in vivo. We show
             that excellent contrast from hemoglobin without any labeling
             can be obtained in tissue. © 2007 Optical Society of
             America.},
   Doi = {10.1364/OL.32.002641},
   Key = {fds234530}
}

@article{fds234297,
   Author = {Mehendale, M and Giordmaine, JA and Gatzogiannis, E and Dogariu, A and Beadie, G and Warren, WS and Scully, MO},
   Title = {All-UV time-resolved CARS},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   ISSN = {2162-2701},
   Abstract = {Time-resolved, coherent anti-Stokes Raman scattering from
             internal vibrations in calcite is reported with all the
             wavelengths in the ultraviolet. Two-photon absorption,
             excitation-dependent dephasing times, and a comparison of
             ultraviolet and visible efficiencies are described. © 2005
             Optical Society of America.},
   Key = {fds234297}
}

@article{fds234301,
   Author = {Huang, F and Federici, JF and Gary, D and Jedju, T and Warren,
             WS},
   Title = {Determining thickness independently from optical constants
             using ultrafast spectral interferometry},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   ISSN = {2162-2701},
   Abstract = {We show that the application of ultrafast techniques,
             specially femtosecond lasers, allow simultaneous
             measurements of material thickness and optical constants
             from transmission measurements using a frequency
             interferometer. © 2005 Optical Society of
             America.},
   Key = {fds234301}
}

@article{fds234304,
   Author = {Ye, T and Fischer, M and Yurtsever, G and Warren,
             WS},
   Title = {Two-photon absorption microscopy of tissue},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   ISSN = {2162-2701},
   Abstract = {Two-photon absorption microscopy (TPAM) has been
             demonstrated to be able to image melanin with high
             sensitivity. TPAM opens up a wide range of nonfluorescent
             molecular targets. © 2005 Optical Society of
             America.},
   Key = {fds234304}
}

@article{fds234308,
   Author = {Rostovtsev, YV and Sariyanni, ZE and Warren, WS and Scully,
             MO},
   Title = {Coherent and stimulated Raman spectroscopy with shaped
             femtosecond pulses in scattering media},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   Abstract = {We show that femtosecond shaped pulses can be used to detect
             coherent and stimulated Raman scattering in multi-scattering
             media. It is possible to perform Raman spectroscopy with
             such specially shaped pulses to determine vibrational
             frequencies and relaxation rates. The technique can be
             applied to spore detection and tissue microscopy. © 2006
             Optical Society of America.},
   Key = {fds234308}
}

@article{fds234309,
   Author = {Rostovtsev, YV and Sariyanni, ZE and Warren, WS and Scully,
             MO},
   Title = {Coherent and stimulated raman spectroscopy with shaped
             femtosecond pulses in scattering media},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   Abstract = {We show that femtosecond shaped pulses can be used to detect
             coherent and stimulated Raman scattering in multi-scattering
             media. It is possible to perform Raman spectroscopy with
             such specially shaped pulses to determine vibrational
             frequencies and relaxation rates. The technique can be
             applied to spore detection and tissue microscopy. © 2006
             Optical Society of America.},
   Key = {fds234309}
}

@article{fds234310,
   Author = {Rostovtsev, YV and Sariyanni, ZE and Warren, WS and Scully,
             MO},
   Title = {Coherent and stimulated Raman spectroscopy with shaped
             femtosecond pulses in scattering media},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   Abstract = {We show that femtosecond shaped pulses can be used to detect
             coherent and stimulated Raman scattering in multi-scattering
             media. It is possible to perform Raman spectroscopy with
             such specially shaped pulses to determine vibrational
             frequencies and relaxation rates. The technique can be
             applied to spore detection and tissue microscopy. © 2006
             Optical Society of America.},
   Key = {fds234310}
}

@article{fds234311,
   Author = {Rostovtsev, YV and Sariyanni, ZE and Warren, WS and Scully,
             MO},
   Title = {Coherent and stimulated Raman spectroscopy with shaped
             femtosecond pulses in scattering media},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   Abstract = {We show that femtosecond shaped pulses can be used to detect
             coherent and stimulated Raman scattering in multi-scattering
             media. It is possible to perform Raman spectroscopy with
             such specially shaped pulses to determine vibrational
             frequencies and relaxation rates. The technique can be
             applied to spore detection and tissue microscopy. © 2006
             Optical Society of America.},
   Key = {fds234311}
}

@article{fds234312,
   Author = {Sariyanni, ZE and Rostovtsev, YV and Warren, WS and Scully,
             MO},
   Title = {Stimulated Raman scattering with shaped femtosecond
             pulses},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   Key = {fds234312}
}

@article{fds234313,
   Author = {Yurtsever, G and Weaver, K and Ye, T and Warren, WS},
   Title = {Two-photon absorption of oxyhemoglobin and methemoglogin for
             microscopic imaging},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   Abstract = {We measured two-photon absorption of oxyhemoglobin and
             methemoglobin with modest laser powers. In combination with
             our previous work on melanin tissue imaging, this shows
             two-photon absorption imaging of hemoglobin state is
             feasible. © 2005 Optical Society of America.},
   Key = {fds234313}
}

@article{fds234315,
   Author = {Warren, WS and Ye, T and Fischer, M and Yurtsever, G and Li, C and Liu, H and Fu, D},
   Title = {Deep tissue imaging with shaped femtosecond laser
             pulses},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2006},
   Month = {January},
   Abstract = {Two-photon absorption and self phase modulation can be
             detected deep in tissue with modest laser powers, using
             shaped femtosecond pulses. This permit microscopic-resolution
             images of biologically important targets. © 2006 Optical
             Society of America.},
   Key = {fds234315}
}

@article{fds234461,
   Author = {Sariyanni, Z-E and Rostovtsev, YV and Warren, WS and Scully,
             MO},
   Title = {Stimulated Raman scattering with shaped femtosecond
             pulses},
   Journal = {Conference on Lasers and Electro-Optics and 2006 Quantum
             Electronics and Laser Science Conference, CLEO/QELS
             2006},
   Year = {2006},
   url = {http://dx.doi.org/10.1109/CLEO.2006.4628895},
   Abstract = {We show that spectral hole refilling can be used to detect
             stimulated Raman scattering to determine vibrational
             frequency of molecules. The technique can be applied to
             spore detection and tissue microscopy. © 2005 Optical
             Society of America.},
   Doi = {10.1109/CLEO.2006.4628895},
   Key = {fds234461}
}

@article{fds234462,
   Author = {Mehendale, M and Giordmaine, JA and Gatzogiannis, E and Dogariu, A and Warren, WS and Beadie, G and Scully, MO},
   Title = {All-ultraviolet time-resolved coherent anti-Stokes Raman
             scattering},
   Journal = {Optics Letters},
   Volume = {31},
   Number = {2},
   Pages = {256-258},
   Year = {2006},
   ISSN = {0146-9592},
   url = {http://dx.doi.org/10.1364/OL.31.000256},
   Abstract = {We report all-UV coherent anti-Stokes Raman scattering
             (CARS) in calcite with 250-280 nm pump, Stokes, probe, and
             anti-Stokes light. UV CARS efficiency is ∼7X higher than
             for comparable scattering in the visible, 480-540 nm.
             Time-resolved UV CARS reveals lengthening of the dephasing
             time of 1086 cm -1 CO32- internal vibrations from 4 to 7 ps
             with increasing vibrational excitation, consistent with a
             phonon depletion model. © 2006 Optical Society of
             America.},
   Doi = {10.1364/OL.31.000256},
   Key = {fds234462}
}

@article{fds234463,
   Author = {Warren, WS},
   Title = {Coherence, correlation and entanglement: Have we learned
             anything from NMR quantum computing?},
   Journal = {AIP Conference Proceedings},
   Volume = {864},
   Pages = {324-330},
   Year = {2006},
   ISSN = {0094-243X},
   url = {http://dx.doi.org/10.1063/1.2400903},
   Abstract = {Nearly a decades' worth of experimental efforts on solution
             NMR quantum computing have confirmed that such systems will
             not be scalable to a useful number of qubits, completely
             consistent with quantum mechanical predictions in 1997.
             However, the theoretical framework has led to new insights
             into the nature of coherence, correlation, and entanglement,
             and may ultimately help enable other magnetic resonance
             applications. © 2006 American Institute of
             Physics.},
   Doi = {10.1063/1.2400903},
   Key = {fds234463}
}

@article{fds234464,
   Author = {Warren, WS},
   Title = {Spectroscopy: Shifting light with spin},
   Journal = {Nature},
   Volume = {442},
   Number = {7106},
   Pages = {990-},
   Year = {2006},
   ISSN = {0028-0836},
   url = {http://dx.doi.org/10.1038/442990a},
   Abstract = {NMR spectroscopy has changed enormously over the years, but
             signal detection has stayed the same since the technique was
             invented. The latest thinking literally shines a new light
             on things. ©2006 Nature Publishing Group.},
   Doi = {10.1038/442990a},
   Key = {fds234464}
}

@article{fds234509,
   Author = {Ye, T and Yurtsever, G and Fischer, M and Simon, JD and Warren,
             WS},
   Title = {Imaging melanin by two-photon absorption
             microscopy},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {6089},
   Year = {2006},
   ISSN = {0277-786X},
   url = {http://dx.doi.org/10.1117/12.646139},
   Abstract = {Multiphoton excitation fluorescence microscopy has proven to
             be a powerful method for non-invasive, in vivo, thick tissue
             imaging with molecular specificity. However, many important
             endogenous biomolecules do not fluoresce (NAD) or fluoresce
             with low efficiency (Melanin). In this report femtosecond
             pulse shaping methods are used to measure two-photon
             absorption (TPA) directly with very high sensitivity.
             Combining with the laser scanning microscope, this
             Two-photon Absorption Microscopy (TPAM) retains the
             penetration and localization advantages of two-photon
             fluorescence microscopy and permits direct observation of
             important endogenous molecular markers (melanin or
             hemoglobin) which are invisible in multiphoton fluorescence
             microscopy. We have demonstrated here for the first time
             that TPAM can successfully and more efficiently image
             melanoma cells and tissues and provide a good melanin
             contrast in optical sectioning of the melanoma lesions which
             are comparable to pathological histology. Combining with the
             two-photon fluorescence images acquired simultaneously, the
             distribution patterns of the melanocytes and their
             intratissue behavior could be studied without cutting the
             lesions from patients. TPAM will undoubtedly find the
             applications in the clinical diagnosis and biomedical
             research.},
   Doi = {10.1117/12.646139},
   Key = {fds234509}
}

@article{fds234296,
   Author = {Mehendale, M and Giordmaine, JA and Gatzogiannis, E and Dogariu, A and Beadie, G and Warren, WS and Scully, MO},
   Title = {All-UV time-resolved CARS},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {1},
   Pages = {363-365},
   Year = {2005},
   Month = {December},
   ISSN = {2162-2701},
   Abstract = {Time-resolved, coherent anti-Stokes Raman scattering from
             internal vibrations in calcite is reported with all the
             wavelengths in the ultraviolet. Two-photon absorption,
             excitation-dependent dephasing times, and a comparison of
             ultraviolet and visible efficiencies are described. © 2005
             Optical Society of America.},
   Key = {fds234296}
}

@article{fds234300,
   Author = {Huang, F and Federici, JF and Gary, D and Jedju, T and Warren,
             WS},
   Title = {Determining thickness independently from optical constants
             using ultrafast spectral interferometry},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {2},
   Pages = {1103-1105},
   Year = {2005},
   Month = {December},
   ISSN = {2162-2701},
   Abstract = {We show that the application of ultrafast techniques,
             specially femtosecond lasers, allow simultaneous
             measurements of material thickness and optical constants
             from transmission measurements using a frequency
             interferometer. © 2005 Optical Society of
             America.},
   Key = {fds234300}
}

@article{fds234302,
   Author = {Ye, T and Fischer, M and Yurtsever, G and Warren,
             WS},
   Title = {Two-photon absorption microscopy of tissue},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {2},
   Pages = {1512-1514},
   Year = {2005},
   Month = {December},
   ISSN = {2162-2701},
   Abstract = {Two-photon absorption microscopy (TPAM) has been
             demonstrated to be able to image melanin with high
             sensitivity. TPAM opens up a wide range of nonfluorescent
             molecular targets. © 2005 Optical Society of
             America.},
   Key = {fds234302}
}

@article{fds234305,
   Author = {Fischer, MC and Ye, T and Yurtsever, G and Miller, A and Ciocca, M and Wagner, W and Warren, WS},
   Title = {Two-photon absorption and self-phase modulation measurements
             with shaped femtosecond laser pulses},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {2},
   Pages = {968-970},
   Year = {2005},
   Month = {December},
   ISSN = {2162-2701},
   Abstract = {We demonstrate experimentally that phase sensitive detection
             of spectral hole refilling can yield information about
             self-phase modulation and two-photon absorption
             coefficients. © 2005 Optical Society of
             America.},
   Key = {fds234305}
}

@article{fds234303,
   Author = {Fischer, MC and Ye, T and Yurtsever, G and Miller, A and Ciocca, M and Wagner, W and Warren, WS},
   Title = {Two-photon absorption and self-phase modulation measurements
             with shaped femtosecond laser pulses},
   Journal = {Optics InfoBase Conference Papers},
   Year = {2005},
   ISSN = {2162-2701},
   Abstract = {We demonstrate experimentally that phase sensitive detection
             of spectral hole refilling can yield information about
             self-phase modulation and two-photon absorption
             coefficients. © 2005 Optical Society of
             America.},
   Key = {fds234303}
}

@article{fds234454,
   Author = {Mehendale, M and Giordmaine, JA and Gatzogiannis, E and Dogariu, A and Beadie, G and Warren, WS and Scully, MO},
   Title = {All-UV time-resolved CARS},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {1},
   Pages = {363-365},
   Year = {2005},
   Abstract = {Time-resolved, coherent anti-Stokes Raman scattering from
             internal vibrations in calcite is reported with all the
             wavelengths in the ultraviolet. Two-photon absorption,
             excitation-dependent dephasing times, and a comparison of
             ultraviolet and visible efficiencies are described. © 2005
             Optical Society of America.},
   Key = {fds234454}
}

@article{fds234455,
   Author = {Huang, F and Federici, JF and Gary, D and Jedju, T and Warren,
             WS},
   Title = {Determining thickness independently from optical constants
             using ultrafast spectral interferometry},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {2},
   Pages = {1103-1105},
   Year = {2005},
   Abstract = {We show that the application of ultrafast techniques,
             specially femtosecond lasers, allow simultaneous
             measurements of material thickness and optical constants
             from transmission measurements using a frequency
             interferometer. © 2005 Optical Society of
             America.},
   Key = {fds234455}
}

@article{fds234457,
   Author = {Chance, B and Nioka, S and Warren, W and Yurtsever,
             G},
   Title = {Mitochondrial NADH as the bellwether of tissue O2
             delivery},
   Journal = {Advances in experimental medicine and biology},
   Volume = {566},
   Pages = {231-242},
   Year = {2005},
   ISSN = {0065-2598},
   url = {http://dx.doi.org/10.1007/0-387-26206-7_31},
   Abstract = {It is proposed that the redox state of mitochondrial NADH1
             will complement blood gas analysis for measuring the health
             and welfare of human tissues. Use of arterial oxygen
             saturation levels (SaO2), especially as assayed by the
             Nellcor instrument, has spread almost everywhere in medicine
             despite the fact that hypoxia of internal organs, liver,
             kidney, brain, pancreas, etc. is not well indicated by
             peripheral digital oxygenation. Indeed, there is an implied
             liability in the failure to infer central oxygenation from
             peripheral values. Near infrared (NIR) sensing of deep
             tissue saturation of hemoglobin (StO2) requires
             multi-wavelength, multi-site measurement of both absorption
             and scattering properties by time or frequency domain NIR
             methods. Corrections for underlying water and lipid
             absorptions can be made so that the correct value for, and
             saturation oh hemoglobin are obtained. Nevertheless, the
             significance of blood oxygen saturation, even localized to
             particular organs, can be questioned from the standpoint of
             what is the critical value of the desaturation from which
             the tissue can recover2; for example, in the case of
             cortical neurons where stroke, compression ischemia, etc.
             cause O2 lack, this value becomes of significant clinical
             importance in both the brain and the spinal chord. These
             approaches are actively pursued and the possibility of
             subsurface redox state measurement in human tissues may
             eventually emerge as the quantitative metric of tissue
             metabolic state and of hypoxic stress. The great flexibility
             and versatility of the fast, economical and "tetherless"
             nature of opto-electronic technology is appropriate to the
             manifold challenges of neuronal function as currently
             measured by intrinsic signals and soon to be studiable by
             extrinsic signals of metabolism and electrophysiological
             functions.},
   Doi = {10.1007/0-387-26206-7_31},
   Key = {fds234457}
}

@article{fds234458,
   Author = {Kocharovsky, V and Cameron, S and Lehmann, K and Lucht, R and Miles, R and Rostovtsev, Y and Warren, W and Welch, GR and Scully,
             MO},
   Title = {Gain-swept superradiance applied to the stand-off detection
             of trace impurities in the atmosphere},
   Journal = {Proceedings of the National Academy of Sciences of the
             United States of America},
   Volume = {102},
   Number = {22},
   Pages = {7806-7811},
   Year = {2005},
   url = {http://dx.doi.org/10.1073/pnas.0500534102},
   Abstract = {We show that gain-swept superradiance can be used to detect
             low (parts per million) concentrations of various gases at
             distances on the order of kilometers, which is done by using
             pulse timing to create small regions of gain at positions
             that sweep toward a detector. The technique is far more
             sensitive than previous methods such as light detection and
             ranging or differential absorption light detection and
             ranging. © 2005 by The National Academy of Sciences of the
             USA.},
   Doi = {10.1073/pnas.0500534102},
   Key = {fds234458}
}

@article{fds234459,
   Author = {Galiana, G and Branca, RT and Warren, WS},
   Title = {Ultrafast intermolecular zero quantum spectroscopy},
   Journal = {Journal of the American Chemical Society},
   Volume = {127},
   Number = {50},
   Pages = {17574-17575},
   Year = {2005},
   ISSN = {0002-7863},
   url = {http://dx.doi.org/10.1021/ja054463m},
   Abstract = {Clinical magnetic resonance spectroscopy is typically
             limited by magnetic inhomogeneities which destroy spectral
             resolution, but intermolecular zero quantum coherences
             (iZQCs) are insensitive to such inhomogeneities. iZQC
             resolution in vivo, however, has been hampered by
             physiological fluctuations over the time scale of the
             two-dimensional acquisition. A faster iZQC sequence will
             allow us to average away these fluctuations, and thus we
             present a new approach to ultrafast two-dimensional
             spectroscopy. This communication reports iZQC experiments
             acquiring up to 31 t1-points per scan, as well as extensions
             to a broad range of other 2D sequences. Copyright © 2005
             American Chemical Society.},
   Doi = {10.1021/ja054463m},
   Key = {fds234459}
}

@article{fds234507,
   Author = {Fischer, MC and Ye, T and Yurtsever, G and Miller, A and Ciocca, M and Wagner, W and Warren, WS},
   Title = {Two-photon absorption and self-phase modulation measurements
             with shaped femtosecond laser pulses},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {2},
   Pages = {968-970},
   Year = {2005},
   Abstract = {We demonstrate experimentally that phase sensitive detection
             of spectral hole refilling can yield information about
             self-phase modulation and two-photon absorption
             coefficients. © 2005 Optical Society of
             America.},
   Key = {fds234507}
}

@article{fds234508,
   Author = {Fischer, MC and Ye, T and Yurtsever, G and Miller, A and Ciocca, M and Wagner, W and Warren, WS},
   Title = {Two-photon absorption and self-phase modulation measurements
             with shaped femtosecond laser pulses},
   Journal = {Optics Letters},
   Volume = {30},
   Number = {12},
   Pages = {1551-1553},
   Year = {2005},
   ISSN = {0146-9592},
   url = {http://dx.doi.org/10.1364/OL.30.001551},
   Abstract = {We show that phase-sensitive detection of spectral hole
             refilling can yield information about self-phase modulation
             and two-photon absorption coefficients. We expect that, when
             applied to tissue microscopy, this technique will allow the
             study of endogenous molecular markers beneath the surface,
             even if those markers are nonfluorescent. © 2005 Optical
             Society of America.},
   Doi = {10.1364/OL.30.001551},
   Key = {fds234508}
}

@article{fds234596,
   Author = {Ye, T and Fischer, M and Yurtsever, G and Warren,
             WS},
   Title = {Two-photon absorption microscopy of tissue},
   Journal = {2005 Conference on Lasers and Electro-Optics,
             CLEO},
   Volume = {2},
   Pages = {1512-1514},
   Year = {2005},
   Abstract = {Two-photon absorption microscopy (TPAM) has been
             demonstrated to be able to image melanin with high
             sensitivity. TPAM opens up a wide range of nonfluorescent
             molecular targets. © 2005 Optical Society of
             America.},
   Key = {fds234596}
}

@article{fds234605,
   Author = {Wagner, W and Li, C and Semmlow, J and Warren, WS},
   Title = {"Rapid phase-cycled two dimensional optical spectroscopy in
             flourescence and transmission mode"},
   Journal = {Optics Express},
   Volume = {13},
   Number = {10},
   Pages = {2697-3706},
   Year = {2005},
   ISSN = {1094-4087},
   url = {http://dx.doi.org/10.1364/OPEX.13.003697},
   Abstract = {Two dimensional magnetic and optical spectra contain
             information about structure and dynamics inaccessible to the
             linear spectroscopist. Recently, phase cycling techniques in
             optical spectroscopy have extended the capabilities of
             two-dimensional electronic spectroscopy. Here, we present a
             method to generate collinear pump/probe pulses at high
             update rates for two-dimensional electronic spectroscopy.
             Both fluorescence mode and transmission mode photon echo
             data from rubidium vapor is presented. © 2005 Optical
             Society of America.},
   Doi = {10.1364/OPEX.13.003697},
   Key = {fds234605}
}

@article{fds304396,
   Author = {Wagner, W and Li, C and Semmlow, J and Warren, WS},
   Title = {Rapid phase-cycled two-dimensional optical spectroscopy in
             fluorescence and transmission mode},
   Journal = {Optics express},
   Volume = {13},
   Number = {10},
   Pages = {3697-3706},
   Year = {2005},
   ISSN = {1094-4087},
   url = {http://dx.doi.org/10.1364/OPEX.13.003697},
   Abstract = {Two dimensional magnetic and optical spectra contain
             information about structure and dynamics inaccessible to the
             linear spectroscopist. Recently, phase cycling techniques in
             optical spectroscopy have extended the capabilities of
             two-dimensional electronic spectroscopy. Here, we present a
             method to generate collinear pump/probe pulses at high
             update rates for two-dimensional electronic spectroscopy.
             Both fluorescence mode and transmission mode photon echo
             data from rubidium vapor is presented. © 2005 Optical
             Society of America.},
   Doi = {10.1364/OPEX.13.003697},
   Key = {fds304396}
}

@article{fds234608,
   Author = {Shannon, KL and Branca, RT and Galiana, G and Cenzano, S and Soboyevo,
             W and Warren, WS},
   Title = {"Simultaneous Acquistion of Multiple Orders of
             Intermolecular Multiple- Quantum Coherence Images in
             Vivo"},
   Journal = {Magnetic Resonanace Imaging},
   Volume = {22},
   Number = {10},
   Pages = {1407-1412},
   Year = {2004},
   Month = {December},
   ISSN = {0730-725X},
   url = {http://dx.doi.org/10.1016/j.mri.2004.10.019},
   Abstract = {Until recently, NMR imaging with intermolecular
             multiple-quantum coherences (iMQCs) has been based on the
             acquisition of a single echo. In vivo studies of iMQC image
             contrast would greatly benefit from a method that could
             acquire several orders of quantum coherence during the same
             acquisition. This would enable comparison of the image
             contrast for various orders and eliminate image
             coregistration problems between scans. It has previously
             been demonstrated that multiple orders of iMQC images can be
             simultaneously acquired of a simple phantom. Here, we
             examine the technique and its effect on biological tissue,
             both in vivo and in vitro. First, we establish the
             effectiveness of the iMQC sequence in vivo using earthworms
             as specimens. We then further show that the multi-CRAZED
             sequence enhances detection of next generation
             (nanoparticle) contrast agents on excised tumor tissue. ©
             2004 Elsevier Inc. All rights reserved.},
   Doi = {10.1016/j.mri.2004.10.019},
   Key = {fds234608}
}

@article{fds234449,
   Author = {Jedju, T and Bosacchi, B and Warren, WS and Nahata, A and Kuenstner,
             T},
   Title = {Generation and detection of pulsed T-Rays for use in the
             study of biological and bio-terrorism issues},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {5411},
   Pages = {92-98},
   Year = {2004},
   ISSN = {0277-786X},
   url = {http://dx.doi.org/10.1117/12.541531},
   Abstract = {Terahertz (T-Rays) spectroscopy has recently emerged as a
             powerful method to access a heretofore barely explored
             region of the electromagnetic spectrum where fundamental
             molecular resonances occur. Besides their importance for
             fundamental research, these resonances could be used as
             signatures in the identification of molecular species and as
             sensitive probes in a wide variety of molecular processes.
             In this paper we consider the potential of THz spectroscopy
             in the application to relevant biomedical and homeland
             security problems such as the analysis of normal and
             diseased tissues and the detection of toxic biomolecules. As
             examples, we present preliminary experimental data which
             suggest that THz spectroscopy 1)can discriminate between
             cancerous and normal tissue, and 2) can reveal the presence
             of foreign substances hidden in an envelope and even allow
             their specific identification. This capability is of
             particular relevance as a straifghtforward homeland security
             tool for the detection of anthrax and other biotoxic
             molecules.},
   Doi = {10.1117/12.541531},
   Key = {fds234449}
}

@article{fds234450,
   Author = {Huang, F and Warren, WS},
   Title = {Direct-detection DWDM and information transmission using
             infrared acousto-optic femtosecond pulse
             shaping},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {5579},
   Number = {PART 2},
   Pages = {652-660},
   Year = {2004},
   ISSN = {0277-786X},
   url = {http://dx.doi.org/10.1117/12.563513},
   Abstract = {Acousto-optic modulator (AOM)-based pulse shaping permits
             precise spectrum slicing, which is useful for dense
             wavelength division multiplexed (DWDM)-based architectures.
             In essence, this method uses microsecond-duration radio
             frequency pulses to completely control the spectra of
             femtosecond laser pulses, hence achieves dramatic temporal
             data compression. We demonstrated the AOM pulse shaper as
             the modulator and a CCD camera with 256 pixels as the
             receiver. The spectrum of a 200 fs Erbium Doped Fiber Laser
             (EDFL) pulse was dispersed across the AOM's aperture (FWHM
             was 35 nm) and was then modulated in a conventional pulse
             shaper. We tested 87 channels with channel-spacing of 0.41
             nm using a 518-MHz modulator, and 120 channels with
             channel-spacing of 0.29 nm using a 148-MHz modulator (in
             each case a 0.1 nm guard band was used). Starting from the
             original pulses, this modulation creates time slots of 43 ps
             and 63.4 ps respectively. The equivalent speed of the
             transmission will be 2.0 Tb/s and 1.9 Tb/s in a highly
             multiplexed system. The spectral efficiencies achieved in
             this experiment were ∼46%, approaching the theoretical
             limit of 50% for On-Off Keying (OOK) modulation. A benchmark
             image was successfully sent over the test
             bed.},
   Doi = {10.1117/12.563513},
   Key = {fds234450}
}

@article{fds234451,
   Author = {Wagner, W and Tian, P and Chunqiang, LI and Semmlow, J and Warren,
             WS},
   Title = {Rapid two-dimensional optical spectroscopy through
             acousto-optic pulse shaping},
   Journal = {Journal of Modern Optics},
   Volume = {51},
   Number = {16-18},
   Pages = {2655-2663},
   Year = {2004},
   ISSN = {0950-0340},
   url = {http://dx.doi.org/10.1080/09500340412331284858},
   Abstract = {Phase-matching techniques are widely used to retrieve
             nonlinear optical signals of electronic and vibrational
             transitions. Here, collinear, phase cycled pulses are used
             to collect the same nonlinear signals in direct analogy to
             nuclear magnetic resonance studies. An acousto-optic pulse
             shaper is used to create suitable sequences of ultrashort
             pulses with arbitrary relative delays and phases. The rapid
             update rate of the acousto-optic modulator allows for
             impressive data rates.},
   Doi = {10.1080/09500340412331284858},
   Key = {fds234451}
}

@article{fds234452,
   Author = {Mehendale, M and Bosacchi, B and Gatzogiannis, E and Dogariu, A and Warren, WS and Scully, MO},
   Title = {Towards an anthrax detector using the femtosecond adaptive
             spectroscopic technique for coherent anti-Stokes Raman
             spectroscopy: Coherent anti-Stokes Raman spectroscopy signal
             from dipicolinic acid in bacterial spores},
   Journal = {Journal of Modern Optics},
   Volume = {51},
   Number = {16-18},
   Pages = {2645-2653},
   Year = {2004},
   ISSN = {0950-0340},
   url = {http://dx.doi.org/10.1080/09500340412331286784},
   Abstract = {We present experimental evidence of a resonant coherent
             antiStokes Raman spectroscopy (CARS) signal from dipicolinic
             acid, a marker molecule in anthrax spores. We also show some
             evidence of resonant CARS signal associated with the
             1000cm-1 resonance from Bacillus Globigii spores which are
             similar to anthrax spores. These results constitute a first
             step towards developing a rapid identification technique for
             bacterial spores.},
   Doi = {10.1080/09500340412331286784},
   Key = {fds234452}
}

@article{fds234505,
   Author = {Ye, T and Wagner, W and Tian, P and Yurtsever, G and Fischer, M and Warren,
             WS},
   Title = {Deep tissue imaging approaches by direct capture of
             two-photon absorption},
   Journal = {2004 2nd IEEE International Symposium on Biomedical Imaging:
             Macro to Nano},
   Volume = {1},
   Pages = {668-671},
   Year = {2004},
   Abstract = {Multiphoton imaging with fluorescence detection has proven
             to be a powerful method for moderately deep tissue imaging
             (less than 1 mm) with molecular specificity. However, many
             important endogenous biomolecules do not fluoresce (NAD) or
             with low efficiency (Melanin). In this paper two femtosecond
             pulse shaping methods have been demonstrated to detect
             two-photon absorption (TPA), instead of fluorescence, with
             high sensitivity, which opens up a wide range of molecular
             targets. It also facilitates longer excitation wavelengths,
             which permit greater tissue penetration. Developing the
             imaging system by using these new methods will be also
             discussed. © 2004 IEEE.},
   Key = {fds234505}
}

@article{fds234601,
   Author = {Keusters, D and Warren, WS},
   Title = {Propagation effects on the peak profile in two-dimensional
             optical photon echo spectroscopy},
   Journal = {Chemical Physics Letters},
   Volume = {383},
   Number = {1-2},
   Pages = {21-24},
   Year = {2004},
   url = {http://dx.doi.org/10.1016/j.cplett.2003.10.130},
   Abstract = {The effect of pulse propagation on the lineshape in a
             two-dimensional photon echo spectrum is investigated using
             the coupled Maxwell Bloch equations. Reshaping of excitation
             and signal pulses due to propagation results in broadening
             of peak profiles. The amount of broadening is not symmetric
             along the two dimensions and depends on pulse intensity and
             relaxation mechanism. It is found that relaxation mechanisms
             that give the same lineshape at low optical density (OD) can
             give different lineshapes at high OD. Even at relatively low
             OD the reshaping can be quite severe, and might result in
             misinterpretation of the obtained spectrum. © 2003
             Published by Elsevier B.V.},
   Doi = {10.1016/j.cplett.2003.10.130},
   Key = {fds234601}
}

@article{fds234609,
   Author = {Bouchard, L-S and Warren, WS},
   Title = {Reconstruction of porous material geometry by stochastic
             optimization based on bulk NMR measurements of the dipolar
             field},
   Journal = {Journal of Magnetic Resonance},
   Volume = {170},
   Number = {2},
   Pages = {299-309},
   Year = {2004},
   url = {http://dx.doi.org/10.1016/j.jmr.2004.05.023},
   Abstract = {The dependence of the bulk signal intensity from a CRAZED
             NMR pulse sequence on magnetic field gradient strength and
             direction as a method to probe the geometry of porous
             materials is investigated. In this article, we report on the
             reconstruction of three-dimensional media consisting of a
             void phase and an NMR-observable liquid phase using the bulk
             intensity of the distant dipolar field. The correlation
             gradient strength and direction provide the spatial encoding
             of the material geometry. An integral equation for the total
             signal intensity is then solved numerically by a simulated
             annealing algorithm to recover the indicator function of the
             fluid phase. Results show that cylindrical and spherical
             structures smaller than the volume contributing to the NMR
             signal can be resolved using three values of the correlation
             distance and three orthogonal gradient directions. This is
             done by minimizing a cost function which measures the
             distance between the bulk signal dependence on gradient
             parameters for the simulated configuration and the signal
             dependence for the target configuration. The algorithm can
             reconstruct and differentiate their spherical and
             cylindrical phase-inverted equivalents. It can also
             differentiate horizontal from vertical cylinders,
             demonstrating the potential for assessing structural
             anisotropy and other coarse geometric quantifiers in a
             porous material. © 2004 Published by Elsevier
             Inc.},
   Doi = {10.1016/j.jmr.2004.05.023},
   Key = {fds234609}
}

@article{fds234610,
   Author = {Huang, SY and Walls, JD and Wang, Y and Warren, WS and Lin,
             Y-Y},
   Title = {Signal irreproducibility in high-field solution magnetic
             resonance experiments caused by spin turbulence},
   Journal = {Journal of Chemical Physics},
   Volume = {121},
   Number = {13},
   Pages = {6105-6109},
   Year = {2004},
   ISSN = {0021-9606},
   url = {http://dx.doi.org/10.1063/1.1802492},
   Abstract = {The turbulent spin dynamics resulting from the joint action
             of radiation damping and distant dipolar field caused signal
             irreversibility in gradient based magnetic resonance
             experiments. The experiments for the stimulated echo variant
             were carried out which emphasize the generality of observed
             signal irreproducibility. The modulated magnetization was
             perturbed to render magic-angle gradients ineffective in
             supressing signal fluctuations. The results show that the
             magic-angle gradients may not completely curb unstable modes
             of growth leading to turbulent spin motion.},
   Doi = {10.1063/1.1802492},
   Key = {fds234610}
}

@article{fds234611,
   Author = {Tang, X-P and Chin, C-L and Bouchard, L-S and Wehrli, FW and Warren,
             WS},
   Title = {Observing Bragg-like diffraction via multiple coupled
             nuclear spins},
   Journal = {Physics Letters, Section A: General, Atomic and Solid State
             Physics},
   Volume = {326},
   Number = {1-2},
   Pages = {114-125},
   Year = {2004},
   url = {http://dx.doi.org/10.1016/j.physleta.2004.04.017},
   Abstract = {Using intermolecular multiple-quantum coherence (iMQC) we
             report the first observation of Bragg-like diffraction via
             multiple distantly coupled nuclear spins. A compact
             quantum-mechanical formalism has been developed for
             analytically calculating iMQCs. The diffraction of iMQCs of
             various orders has been studied in a two-dimensional array
             structure. It indicates that phase cycling and flip angle
             selection are crucial for accurately measuring iMQC and the
             specific iMQCs measured in previous studies were likely
             contaminated by undesired coherences. We have also examined
             the capability and the current limitation of applying iMQCs
             for structural studies. The observation of iMQC diffraction
             introduces a new method for studying collective dynamics. ©
             2004 Elsevier B.V. All rights reserved.},
   Doi = {10.1016/j.physleta.2004.04.017},
   Key = {fds234611}
}

@article{fds304395,
   Author = {Shannon, KL and Branca, RT and Galiana, G and Cenzano, S and Bouchard,
             L-S and Soboyejo, W and Warren, WS},
   Title = {Simultaneous acquisition of multiple orders of
             intermolecular multiple-quantum coherence images in
             vivo},
   Journal = {Magnetic Resonance Imaging},
   Volume = {22},
   Number = {10 SPEC. ISS.},
   Pages = {1407-1412},
   Year = {2004},
   ISSN = {0730-725X},
   url = {http://dx.doi.org/10.1016/j.mri.2004.10.019},
   Abstract = {Until recently, NMR imaging with intermolecular
             multiple-quantum coherences (iMQCs) has been based on the
             acquisition of a single echo. In vivo studies of iMQC image
             contrast would greatly benefit from a method that could
             acquire several orders of quantum coherence during the same
             acquisition. This would enable comparison of the image
             contrast for various orders and eliminate image
             coregistration problems between scans. It has previously
             been demonstrated that multiple orders of iMQC images can be
             simultaneously acquired of a simple phantom. Here, we
             examine the technique and its effect on biological tissue,
             both in vivo and in vitro. First, we establish the
             effectiveness of the iMQC sequence in vivo using earthworms
             as specimens. We then further show that the multi-CRAZED
             sequence enhances detection of next generation
             (nanoparticle) contrast agents on excised tumor tissue. ©
             2004 Elsevier Inc. All rights reserved.},
   Doi = {10.1016/j.mri.2004.10.019},
   Key = {fds304395}
}

@article{fds234438,
   Author = {Keusters, D and Tian, P and Warren, WS},
   Title = {Ultrafast two-photon free induction decay},
   Journal = {Springer Series in Chemical Physics},
   Volume = {71},
   Pages = {85-87},
   Year = {2003},
   ISSN = {0172-6218},
   Abstract = {Phase sensitive measurement of two-photon induced coherence
             is demonstrated, using phase coherent pulse pairs. By using
             an acousto-optic pulse shaper the different coherence
             transfer pathways in the two-photon absorption process can
             be separated.},
   Key = {fds234438}
}

@article{fds234439,
   Author = {Tan, H-S and Schreiber, E and Warren, WS},
   Title = {Infrared pulse shaping by parametric amplification},
   Journal = {Springer Series in Chemical Physics},
   Volume = {71},
   Pages = {202-204},
   Year = {2003},
   ISSN = {0172-6218},
   Abstract = {We create arbitrarily shaped ultrashort pulses in the mid
             infrared (∼3.0μm). The amplitude and phase profile of a
             shaped broadband near infrared signal pulse is transferred
             to the mid infrared idler pulse in a KNbO3 optical
             parametric amplification system pumped with a 805nm narrow
             bandwidth pump pulse.},
   Key = {fds234439}
}

@article{fds234440,
   Author = {Mehendale, M and Bosacchi, B and Warren, WS and Scully,
             MO},
   Title = {Towards a FAST-CARS anthrax detector: CARS signal from
             dipicolinic acid},
   Journal = {Conference Proceedings - Lasers and Electro-Optics Society
             Annual Meeting-LEOS},
   Volume = {1},
   Pages = {311-312},
   Year = {2003},
   Abstract = {An overview is given of experimental results towards the
             realization of an alternative optical technique, the FAST
             CARS (Femtosecond Adaptive Spectroscopic Technique for
             Coherent Anti-Stokes Raman Spectroscopy) approach. This
             proposal makes use of the CARS configuration, thus
             exploiting the specificity of the vibrational spectra, and
             attempts to maximize the signal intensity through a few
             enhancement mechanisms.},
   Key = {fds234440}
}

@article{fds234441,
   Author = {Cao, H and Warren, WS and Dogariu, A and Wang, LJ},
   Title = {Reduction of optical intensity noise by means of two-photon
             absorption},
   Journal = {Journal of the Optical Society of America
             B},
   Volume = {20},
   Number = {3},
   Pages = {560-563},
   Year = {2003},
   ISSN = {0740-3224},
   Abstract = {We demonstrate an all-optical intensity noise reduction
             technique by using two-photon absorption of ZnSe in a Z-scan
             configuration. We measure the nonlinear transmission and the
             shot-to-shot energy fluctuations of 860-nm intense
             femtosecond laser pulses. At a 40% nonlinear transmission
             level the noise in the pulse train is reduced to 24%. This
             yields an additional 40% reduction in the relative pulse
             energy fluctuation. A realistic theoretical treatment is
             presented and is found to be in good agreement with
             experimental results. © 2003 Optical Society of
             America.},
   Key = {fds234441}
}

@article{fds234442,
   Author = {Keusters, D and Warren, WS},
   Title = {Effect of pulse propagation on the two-dimensional photon
             echo spectrum of multilevel systems},
   Journal = {Journal of Chemical Physics},
   Volume = {119},
   Number = {8},
   Pages = {4478-4489},
   Year = {2003},
   url = {http://dx.doi.org/10.1063/1.1591175},
   Abstract = {A perturbative method was used to investigate the effect of
             propagation on multilevel systems, specifically on the
             relative intensity and profile of the cross peaks. It was
             shown that both the peak profiles and the relative intensity
             of the peaks in a 2D spectrum change as the pulse propagates
             through the sample. The behavior of the peaks was found to
             be counterintuitive, and depends not only on the optical
             density, but also on the dynamics of the
             system.},
   Doi = {10.1063/1.1591175},
   Key = {fds234442}
}

@article{fds234443,
   Author = {Tan, H-S and Warren, WS},
   Title = {Mid infrared pulse shaping by optical parametric
             amplification and its application to optical free induction
             decay measurement},
   Journal = {Optics express},
   Volume = {11},
   Number = {9},
   Pages = {1021-1028},
   Year = {2003},
   ISSN = {1094-4087},
   Abstract = {We produce microjoule energy shaped mid infrared (MIR)
             pulses in an optical parametric amplification (OPA) process
             by imposing the phase and amplitude profile of an
             arbitrarily shaped pump pulse onto the idler pulse. Using
             phase locked pulses created using this technique, we measure
             for the first time, complex optical free induction decay
             (OFID) of the vibrational coherence of a C-H stretching
             mode. © 2003 Optical Society of America.},
   Key = {fds234443}
}

@article{fds234444,
   Author = {Tian, P and Keusters, D and Suzaki, Y and Warren,
             WS},
   Title = {Femtosecond phase-coherent two-dimensional
             spectroscopy},
   Journal = {Science},
   Volume = {300},
   Number = {5625},
   Pages = {1553-1555},
   Year = {2003},
   url = {http://dx.doi.org/10.1126/science.1083433},
   Abstract = {Femtosecond phase-coherent two-dimensional (2D) spectroscopy
             has been experimentally demonstrated as the direct optical
             analog of 2D nuclear magnetic resonance. An acousto-optic
             pulse shaper created a collinear three-pulse sequence with
             well-controlled and variable interpulse delays and phases,
             which interacted with a model atomic system of rubidium
             vapor. The desired nonlinear polarization was selected by
             phase cycling (coadding experimental results obtained with
             different interpulse phases). This method may enhance our
             ability to probe the femtosecond structural dynamics of
             macromolecules.},
   Doi = {10.1126/science.1083433},
   Key = {fds234444}
}

@article{fds234445,
   Author = {Keusters, D and Tan, H-S and O'Shea, P and Zeek, E and Trebino, R and Warren, WS},
   Title = {Relative-phase ambiguities in measurements of ultrashort
             pulses with well-separated multiple frequency
             components},
   Journal = {Journal of the Optical Society of America
             B},
   Volume = {20},
   Number = {10},
   Pages = {2226-2237},
   Year = {2003},
   ISSN = {0740-3224},
   Abstract = {A study is performed on relative-phase ambiguities in
             measurements of ultrashort pulses with well-separated
             multiple frequency components. It is shown that if a laser
             pulse consists of components that are well separated in the
             frequency domain, the self-referenced pulse characterization
             techniques are incapable of yielding the overall phase
             relation among the spectral components of the pulse. If a
             well-characterized reference pulse is available, spectral
             interferometry can determine the phase relation.},
   Key = {fds234445}
}

@article{fds234446,
   Author = {Chin, C-L and Tang, X and Bouchard, L-S and Saha, PK and Warren, WS and Wehrli, FW},
   Title = {Isolating quantum coherences in structural imaging using
             intermolecular double-quantum coherence MRI},
   Journal = {Journal of Magnetic Resonance},
   Volume = {165},
   Number = {2},
   Pages = {309-314},
   Year = {2003},
   url = {http://dx.doi.org/10.1016/j.jmr.2003.08.007},
   Abstract = {Intermolecular multiple-quantum coherence (iMQC) MR imaging
             provides a fundamentally different contrast mechanism. It
             allows probing tissue microstructure by tuning the direction
             and strength of the correlation gradient. However, iMQC
             images of a specific quantum-coherence can easily be
             contaminated by leakage signals from undesired quantum
             coherences (zero, single, and triple quantum coherence in
             this work). Using a modified double-quantum CRAZED imaging
             sequence, we show that signals originating from various
             coherence orders (M=0, 1, 2, 3) can be predicted in k-space
             and effectively isolated by means of a four-step phase
             cycling scheme and judicious choice of flip angles. Finally,
             preliminary data suggest the method to be able to provide
             information on trabecular bone architecture such as regional
             mean trabecular plate separation. © 2003 Elsevier Inc. All
             rights reserved.},
   Doi = {10.1016/j.jmr.2003.08.007},
   Key = {fds234446}
}

@article{fds234447,
   Author = {Tang, X and Ong, H and Shannon, K and Warren, WS},
   Title = {Simultaneous acquisition of multiple orders of
             intermolecular multiple-quantum coherence
             images},
   Journal = {Magnetic Resonance Imaging},
   Volume = {21},
   Number = {10},
   Pages = {1141-1149},
   Year = {2003},
   url = {http://dx.doi.org/10.1016/j.mri.2003.08.015},
   Abstract = {Recent studies have demonstrated the ability to detect
             images based on intermolecular multiple-quantum coherences
             (iMQCs) that correspond to flipping of two or more separated
             spins simultaneously, as opposed to conventional magnetic
             resonance where only one spin is flipped at a time. Until
             now, iMQC imaging has only acquired one coherence signal per
             pulse sequence. Here we report a new sequence that
             successfully detects five orders of coherence (2, 1, 0, -1,
             and -2-quantum coherence images) in one pulse sequence, with
             each signal having its full intensity. The simultaneous
             acquisition highlights substantial contrast differences
             between conventional and iMQC images, and between the
             different types of iMQC images. © 2003 Elsevier Inc. All
             rights reserved.},
   Doi = {10.1016/j.mri.2003.08.015},
   Key = {fds234447}
}

@article{fds234448,
   Author = {Warren, WS and Wagner, W and Ye, T},
   Title = {The prospects for high resolution optical brain imaging: The
             magnetic resonance perspective},
   Journal = {Magnetic Resonance Imaging},
   Volume = {21},
   Number = {10},
   Pages = {1225-1233},
   Year = {2003},
   url = {http://dx.doi.org/10.1016/j.mri.2003.08.024},
   Abstract = {Various analogs of NMR and MRI are now technically possible
             in optics; specifically, high-resolution laser-pulse shaping
             and complex pulse sequence generation with well-defined
             phase shifts has been demonstrated. Here we summarize this
             technology and discuss the potential for these methods to
             enhance optical functional imaging, competing with (and
             surpassing?) what is possible by functional MRI. © 2003
             Elsevier Inc. All rights reserved.},
   Doi = {10.1016/j.mri.2003.08.024},
   Key = {fds234448}
}

@article{fds234599,
   Author = {Bouchard, L-S and Tang, X and Chin, C and Wehrli, FW and Warren,
             WS},
   Title = {"Magnetic Resonance Imaging of the Distant Dipolar Field in
             Structured Samples Using Intermolecular Multiple-Quantum
             Coherences of Various Orders"},
   Journal = {Proc. Intl. Soc. Mag. Reson. Med.},
   Number = {11},
   Pages = {1110},
   Year = {2003},
   Key = {fds234599}
}

@article{fds234600,
   Author = {Bouchard, L-S and Poptani, H and Rizi, RR and Glickson, JD and Warren,
             WS},
   Title = {"Intermolecular Mulitple-Quantum Coherence of Imaging of
             Murine Tumors Depends on Choice of Dipolar Correlation
             Distance"},
   Journal = {Proc. Intl. Soc. Mag. Reson. Med.},
   Number = {11},
   Pages = {1112},
   Year = {2003},
   Key = {fds234600}
}

@article{fds234606,
   Author = {Bosacchi, B and Mehendale, M and Warren, WS and Rabitz, H and Scully,
             MO},
   Title = {Computational Intelligence in Bacterial Spore Detection
             & Identification},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {5200},
   Pages = {31-45},
   Year = {2003},
   ISSN = {0277-786X},
   Abstract = {Optical techniques are very promising for detecting and
             identifying bacterial spores. They are potentially superior
             to the existing "wet chemistry" approaches regarding several
             important features of an effective alarm system, such as
             speed, in-field use, continuous monitoring, and reliability.
             In this paper we discuss the role that computational
             intelligence (CI) can play in the control and optimization
             of optical experiments, and in the analysis and
             interpretation of the large amount of data they provide.
             After a brief discussion of the use of CI in the
             classification of optical spectra, we introduce the recently
             proposed FAST CARS (Femtosecond Adaptive Spectroscopic
             Techniques for Coherent Anti-Stokes Raman Scattering)
             technique. Here the role of CI is essential: using an
             adaptive feedback approach based on genetic algorithms, the
             hardware system evolves and organizes itself to optimize the
             intensity of the CARS signal.},
   Key = {fds234606}
}

@article{fds234607,
   Author = {Mehendale, M and Bosacchi, B and Warren, WS and Scully,
             MO},
   Title = {Evolutionary Pulse Shaping in CARS Signal
             Enhancement},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {5200},
   Pages = {46-55},
   Year = {2003},
   ISSN = {0277-786X},
   Abstract = {We discuss the role of evolutionary adaptive algorithms in
             shaping femtosecond pulses with an eye toward their use in
             the quantum control of optical properties. In particular, we
             report preliminary results from an ongoing attempt to
             implement the recently proposed FAST CARS technique for the
             detection and identification of bacterial spores. In the
             initial phase of this project, we are studying the CARS
             signal from a deuterated water (D2O) solution of Dipicolinic
             Acid (DPA), which is an important constituent of the spores.
             We have detected CARS signal associated with the DPA
             vibrational resonances at ∼ 1,600 and ∼ 3,000cm-1. We
             also find preliminary evidence of a pulse shaping
             enhancement of the CARS intensity. This effect is weak, but
             significant. It is premature to ascribe it to any particular
             mechanism, but its detection encourages its optimization by
             searching the space of all possible pulse shapes via an
             evolutionary feedback algorithm.},
   Key = {fds234607}
}

@article{fds234432,
   Author = {Yang, W and Kobayashi, H and Warren, WS},
   Title = {Frequency-domain differential phase-shift keying (FD-DPSK)
             of ultrafast laser pulses},
   Journal = {IEEE Photonics Technology Letters},
   Volume = {14},
   Number = {2},
   Pages = {215-217},
   Year = {2002},
   ISSN = {1041-1135},
   url = {http://dx.doi.org/10.1109/68.980526},
   Abstract = {The frequency-domain differential phase-shift-keying (DPSK)
             using ultrafast laser pulses has been demonstrated. Spectral
             coding based on acoustic optical modulator pulse shaping is
             used for modulation, and the ultrafast pulse
             characterization based on spectral interferometry is used
             for demodulation. The encoded differential phase pattern is
             successfully retrieved after transmission over 4-km
             dispersion-shifted fiber, which induces substantial
             nonlinear distortions.},
   Doi = {10.1109/68.980526},
   Key = {fds234432}
}

@article{fds234433,
   Author = {Lin, Y-Y and Huang, SY and Lisitza, N and Warren,
             WS},
   Title = {Spin chaos in magnetic resonance},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {4787},
   Pages = {124-131},
   Year = {2002},
   url = {http://dx.doi.org/10.1117/12.455874},
   Abstract = {The joint action of two readily observed effects in solution
             magnetic resonance- radiation damping and the dipolar
             field-are shown to generate spatiotemporal chaos in routine
             experiments. The extreme sensitivity of the chaotic spin
             dynamics to experimental conditions during the initial
             evolution period can be used to construct a spin amplifier
             to enhance sensitivity and contrast in magnetic resonance
             spectroscopy and imaging. Alternatively, amplification of
             intrinsic spin noise or tiny experimental perturbations such
             as temperature gradient fluctuations leads to signal
             interferences and highly irreproducible measurements.
             Controlling the underlying chaotic evolution provides the
             crucial link between amplifying weak signals and
             counteracting unwanted signal fluctuations.},
   Doi = {10.1117/12.455874},
   Key = {fds234433}
}

@article{fds234434,
   Author = {Warren, WS and Huang, SY and Ahn, S and Lin, YY},
   Title = {Understanding third-order dipolar effects in solution
             nuclear magnetic resonance: Hahn echo decays and
             intermolecular triple-quantum coherences},
   Journal = {Journal of Chemical Physics},
   Volume = {116},
   Number = {5},
   Pages = {2075-2084},
   Year = {2002},
   url = {http://dx.doi.org/10.1063/1.1419061},
   Abstract = {The coupled-spin framework is used to take into account the
             properties of the "third-order experiments," namely Hahn
             echo decay and triple-quantum CRAZED. It is shown that the
             Hahn echo decay reflects the unique contrast present in
             other CRAZED experiments, but that double-quantum and
             zero-quantum experiments are more useful.},
   Doi = {10.1063/1.1419061},
   Key = {fds234434}
}

@article{fds234435,
   Author = {Tan, H-S and Schreiber, E and Warren, WS},
   Title = {High-resolution indirect pulse shaping by parametric
             transfer},
   Journal = {Optics Letters},
   Volume = {27},
   Number = {6},
   Pages = {439-441},
   Year = {2002},
   ISSN = {0146-9592},
   Abstract = {The phase and amplitude profile of a shaped pulse in the
             visible is transferred to a pulse in the near-infrared via
             an optical parametric amplification (OPA) process. Complex
             shaped pulses, such as multiple-pulse trains and pulses with
             high-order phase chirp, are produced at 1.2 μm. Theoretical
             conditions necessary for high-fidelity parametric shape
             transfer are discussed. Similar schemes can be implemented
             for other OPA systems pumped at near-infrared wavelengths to
             generate high-resolution shaped pulses in the mid-infrared.
             © 2002 Optical Society of America.},
   Key = {fds234435}
}

@article{fds234436,
   Author = {Huang, SY and Lin, Y-Y and Lisitza, N and Warren,
             WS},
   Title = {Signal interferences from turbulent spin dynamics in
             solution nuclear magnetic resonance spectroscopy},
   Journal = {Journal of Chemical Physics},
   Volume = {116},
   Number = {23},
   Pages = {10325-10337},
   Year = {2002},
   url = {http://dx.doi.org/10.1063/1.1467333},
   Abstract = {The signal interference from turbulent spin dynamics in
             solution nuclear magnetic resonance spectroscopy was
             discussed. The unexpected dynamics, triggered by the joint
             action of the radiation damping and the distant dipolar
             field deteriorates the performances of the certain pulse
             sequences incorporating weak pulsed field gradients and long
             evolution times. The effects were demonstrated in three
             general classes of gradient NMR applications including
             solvent signal suppression, diffusion measurements, and
             coherence pathway selection.},
   Doi = {10.1063/1.1467333},
   Key = {fds234436}
}

@article{fds234437,
   Author = {Bouchard, L-S and Rizi, RR and Warren, WS},
   Title = {Magnetization structure contrast based on intermolecular
             multiple-quantum coherences},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {48},
   Number = {6},
   Pages = {973-979},
   Year = {2002},
   url = {http://dx.doi.org/10.1002/mrm.10293},
   Abstract = {In vivo and ex vivo MRI based on intermolecular
             multiple-quantum coherences (iMQC) is predicted to provide a
             fundamentally different source of contrast for MRI. This
             article investigates the dependence of image contrast upon
             the choice of correlation distance for a heterogeneous
             material. A closely packed array of parallel hollow
             cylinders was used to demonstrate signal intensity
             variations when the correlation distance becomes comparable
             to the gap size between the cylinders. The observed effects
             agree well with three-dimensional calculations of the time
             evolution of magnetization under the nonlinear Bloch
             equations. © 2002 Wiley-Liss, Inc.},
   Doi = {10.1002/mrm.10293},
   Key = {fds234437}
}

@article{fds234595,
   Author = {Tian, P and Keusters, D and Warren, WS},
   Title = {Direct and sensitive measurement of two-photon absorption
             cross sections},
   Journal = {Pacific Rim Conference on Lasers and Electro-Optics, CLEO -
             Technical Digest},
   Pages = {447-448},
   Year = {2002},
   Abstract = {Direct and sensitive measurement of two-photon absorption
             (TPA) cross sections was presented. As a proof of principle,
             δ was measured for rhodamine 6G (R6G) in methanol. Results
             showed that the technique using moderate power from a
             mode-locked laser gave sensitivity of 10-6
             cm/GW.},
   Key = {fds234595}
}

@article{fds234420,
   Author = {Cao, H and Dogariu, A and Kuzmich, A and Warren, WS and Wang,
             LJ},
   Title = {An all-optical noise eater},
   Journal = {Conference on Lasers and Electro-Optics Europe - Technical
             Digest},
   Pages = {509-510},
   Year = {2001},
   Abstract = {The shot-to-shot energy fluctations of a laser was reduced
             using nonlinear absorption. Two-photon absorption (2PA) was
             used as the optical limiting mechanism. The histograms of
             input and output pulses were examined and standard
             deviatation for each set was calculated. Reduction in noise
             figure was demonstrated by allowing reduced throughput of
             the device.},
   Key = {fds234420}
}

@article{fds234422,
   Author = {Huang, F and Warren, WS},
   Title = {Phase lock loop control of two optical pulses and pulse
             shaping at 1.55 μm},
   Journal = {Conference on Lasers and Electro-Optics Europe - Technical
             Digest},
   Pages = {268-269},
   Year = {2001},
   Abstract = {Feedback phase control of two optical pulses and its
             application for the optimization of acousto-optic pulse
             shaping was investigated. The difference between the
             reference pulse and target, provided feedback to the RF
             control signal and permitted closed loop optimization. The
             comparison of spectral interference pattern to one obtained
             after a π/2 phase shift in AOM driving voltage resolved the
             sign ambiguity with phase leading or lagging the reference
             point and doubled the dynamic range.},
   Key = {fds234422}
}

@article{fds234423,
   Author = {Yang, W and Kobayashi, H and Warren, WS},
   Title = {Ultrafast laser pulse spectral domain differential phase
             shift keying},
   Journal = {Conference on Optical Fiber Communication, Technical Digest
             Series},
   Volume = {54},
   Number = {3},
   Pages = {WDD45/1-WDD45/3},
   Year = {2001},
   Abstract = {Pulse spectral-domain differential-phase-shift-keying has
             been demonstrated using AOM-based pulse shaping for
             modulation and spectral interferometry for demodulation. The
             encoded differential phase is successfully retrieved despite
             of the nonlinear distortions after 4-km dispersion-shifted
             fiber transmission.},
   Key = {fds234423}
}

@article{fds234424,
   Author = {Tan, H-S and Warren, WS and Schreiber, E},
   Title = {Amplified shaped ultrashort pulses in the visible by a
             double stage non-collinear optical parametric
             process},
   Journal = {Conference on Lasers and Electro-Optics Europe - Technical
             Digest},
   Pages = {49-},
   Year = {2001},
   Abstract = {A double stage noncollinear optical parametric process was
             used to generate amplified shaped ultrashort pulses in the
             visible light range. The pulses were shaped in the spectral
             domain by the Acousto-optic modulation (AOM) technique.
             Pulse shapes were characterized by a cross-correlation
             variant of the spectrally and temporally resolved
             upconversion technique (STRUT). Amplification of the shaped
             pulse by the non-collinear optical process recovered a
             significant amount of energy lost in the pulse shaping
             process.},
   Key = {fds234424}
}

@article{fds234425,
   Author = {Yang, W and Fetterman, MR and Goswami, D and Warren,
             WS},
   Title = {High-ratio electro-optical data compression for massive
             accessing networks using AOM-based ultrafast pulse
             shaping},
   Journal = {Journal of Optical Communications},
   Volume = {22},
   Number = {1},
   Pages = {15-18},
   Year = {2001},
   Abstract = {Electro-optical data compression was demonstrated using the
             acousto-optic modulator (AOM) based ultrafast pulse shaping
             techniques. The comparison of electronic data packet into an
             optical data packet with effective data rate was
             demonstrated. The AOM-based pulse shaping compressed a
             14-bit data frame of slower electronic signal into one
             single 20 picosecond time slot of the optical channel. The
             high ratio data compression technique enabled electronic
             end-user to share the optical channel directly.},
   Key = {fds234425}
}

@article{fds234426,
   Author = {Zhang, H and Lizitsa, N and Bryant, RG and Warren,
             WS},
   Title = {Experimental characterization of intermolecular
             multiple-quantum coherence pumping efficiency in solution
             NMR},
   Journal = {Journal of Magnetic Resonance},
   Volume = {148},
   Number = {1},
   Pages = {200-208},
   Year = {2001},
   ISSN = {1090-7807},
   url = {http://dx.doi.org/10.1006/jmre.2000.2195},
   Abstract = {The behavior of intermolecular multiple-quantum coherences
             in a variety of simple liquids with different chemical and
             magnetic properties is investigated experimentally and
             modeled by numerical simulations based on modified Bloch
             equations. The effects of spin concentration, temperature,
             intramolecular conformational flexibility, chemical
             exchange, and spin-spin coupling on the formation of
             high-order coherences are examined. It is shown that any
             process that makes the Larmor frequency time-dependent may
             interfere with the formation of these coherences. Good
             agreement is achieved between experiments and simulation,
             using independently known values of the magnetization
             density, the rate constants for translational diffusion,
             spin-spin and spin-lattice relaxation, and radiation
             damping. © 2001 Academic Press.},
   Doi = {10.1006/jmre.2000.2195},
   Key = {fds234426}
}

@article{fds234427,
   Author = {Huang, F and Yang, W and Warren, WS},
   Title = {Quadrature spectral interferometric detection and pulse
             shaping},
   Journal = {Optics Letters},
   Volume = {26},
   Number = {6},
   Pages = {382-384},
   Year = {2001},
   ISSN = {0146-9592},
   Abstract = {We introduce a new variant of spectral interferometry, using
             spectrally dispersed ultrafast laser pulses and quadrature
             detection to measure optical thickness variations related to
             surface structure. We can resolve surface features with
             depths of 3 mm to 25 nm, using a lateral resolution of
             ∼100 μm. Quadrature detection gives a larger dynamic
             range and solves the sign ambiguity problem. This method has
             potential applications in device manufacture, optical
             communications, and error compensation in pulse shaping. ©
             2001 Optical Society of America.},
   Key = {fds234427}
}

@article{fds234428,
   Author = {Tan, H-S and Warren, WS and Schreiber, E},
   Title = {Generation, amplification and characterization of tunable
             visible ultrashort shaped pulses},
   Journal = {Springer Series in Chemical Physics},
   Volume = {66},
   Pages = {105-107},
   Year = {2001},
   ISSN = {0172-6218},
   Abstract = {By producing non-collinear optical amplification (NOPA) with
             an internal acousto-optic modulator (AOM), we generate
             amplified shaped ultrashort pulses (∼5μJ, <50fs)
             tunable from 500 to 700nm with up to 50THz bandwidths. The
             shaped pulses are fully characterized by a variation of the
             spectrally and temporally resolved up-conversion technique
             (STRUT).},
   Key = {fds234428}
}

@article{fds234429,
   Author = {Keusters, D and Tian, P and Warren, WS},
   Title = {Femtosecond polarization detection using high-speed pulse
             shaping},
   Journal = {Springer Series in Chemical Physics},
   Volume = {66},
   Pages = {165-167},
   Year = {2001},
   ISSN = {0172-6218},
   Abstract = {We demonstrate a method for femtosecond, phase sensitive
             detection of optical polarization, using an acousto-optic
             pulse shaper to create a sequence of up to several hundred
             phase coherent pulses. Essential to this method is the
             ability of the acousto-optic pulse shaper to update the
             phase relation of the pulses in the sequence on a nanosecond
             timescale. The method is demonstrated by measuring the
             optical free induction decay of rubidium vapor, and can be
             particularly useful for experiments involving very low or
             very high optical densities. It can easily be extended to
             multidimensional spectroscopy.},
   Key = {fds234429}
}

@article{fds234430,
   Author = {Tan, H-S and Warren, WS and Schreiber, E},
   Title = {Generation and amplification of ultrashort shaped pulses in
             the visible by a two-stage noncollinear optical parametric
             process},
   Journal = {Optics Letters},
   Volume = {26},
   Number = {22},
   Pages = {1812-1814},
   Year = {2001},
   ISSN = {0146-9592},
   Abstract = {We report the generation and amplification of ultrashort
             shaped pulses in the visible by a two-stage non-collinear
             optical parametric amplification process. Phase and
             amplitude profiles of the shaped pulses are conserved in our
             amplification scheme. The energy losses normally associated
             with the production of complex shaped pulses are eliminated.
             © 2001 Optical Society of America.},
   Key = {fds234430}
}

@article{fds234431,
   Author = {Fetterman, MR and Davis, JC and Tan, H-S and Yang, W and Goswami, D and Rhee, J-K and Warren, WS},
   Title = {Fast-frequency-hopping modulation and detection
             demonstration},
   Journal = {Journal of the Optical Society of America
             B},
   Volume = {18},
   Number = {9},
   Pages = {1372-1376},
   Year = {2001},
   ISSN = {0740-3224},
   Abstract = {We demonstrate fast-frequency-hopping modulation that
             exploits the unique features of acousto-optic-modulator
             based laser pulse shaping and the spectrally and temporally
             resolved upconversion technique (STRUT) pulse-characterization
             method. These pulses have been specifically designed so that
             they can be characterized by the STRUT, without any
             processing of the STRUT data set. We present examples of
             complex fast-frequency-hopping laser pulses that have been
             generated and characterized by our pulse-shaping system and
             STRUT. We discuss the theoretical limitations on the data
             rate that can be obtained with such a technique. © 2001
             Optical Society of America.},
   Key = {fds234431}
}

@article{fds234594,
   Author = {Warren, WS},
   Title = {Multidimensional symmetry in a three-dimensional
             world},
   Journal = {Science},
   Volume = {294},
   Number = {5546},
   Pages = {1475-1476},
   Year = {2001},
   url = {http://dx.doi.org/10.1126/science.1066542},
   Doi = {10.1126/science.1066542},
   Key = {fds234594}
}

@article{fds234410,
   Author = {Yang, W and Fetterman, MR and Davis, JC and Warren,
             WS},
   Title = {Spectral interference measurement of nonlinear pulse
             propagation dynamics in optical fibers},
   Journal = {Optics Letters},
   Volume = {25},
   Number = {1},
   Pages = {22-24},
   Year = {2000},
   ISSN = {0146-9592},
   Abstract = {Ultrafast pulse shaping and ultrafast pulse spectral
             phase-retrieval techniques are used in the spectral
             interference measurement of nonlinear pulse propagation
             dynamics in dispersion-shifted optical fiber. Nonlinear
             responses in both amplitude profile and phase profile of the
             pulses at zero-dispersion wavelength as well as at
             nonzero-dispersion wavelength are directly measured. A
             numerical simulation that uses a third-oder-dispersion-included
             nonlinear Schrödinger equation gives excellent agreement
             with the experimental data. © 2000 Optical Society of
             America.},
   Key = {fds234410}
}

@article{fds234411,
   Author = {Rizi, RR and Ahn, S and Alsop, DC and Garrett-Roe, S and Mescher, M and Richter, W and Schnall, MD and Leigh, JS and Warren,
             WS},
   Title = {Intermolecular zero-quantum coherence imaging of the human
             brain},
   Journal = {Magnetic Resonance in Medicine},
   Volume = {43},
   Number = {5},
   Pages = {627-632},
   Year = {2000},
   url = {http://dx.doi.org/10.1002/(SICI)1522-2594(200005)43:5<627::AID-MRM2>3.0.CO;2-J},
   Abstract = {The first intermolecular zero-quantum coherence (iZQC) MR
             images of the human brain at 4T are presented. To generate
             iZQC images, a modified echo- planar imaging pulse sequence
             was used which included an additional 45°RF pulse and a
             correlation gradient. The observability and nonconventional
             contrast of human brain iZQC images at 4T is demonstrated.
             Axial images are presented for various pulse sequence
             parameters, and a zero-quantum relaxation map is obtained.
             (C) 2000 Wiley-Liss, Inc.},
   Doi = {10.1002/(SICI)1522-2594(200005)43:5<627::AID-MRM2>3.0.CO;2-J},
   Key = {fds234411}
}

@article{fds234412,
   Author = {Richter, W and Richter, M and Warren, W and Merkle, H and Adriany, G and Andersen, P and Ugtirbil, K},
   Title = {Functional MRI with intermolecular multiple quantum
             coherences},
   Journal = {NeuroImage},
   Volume = {11},
   Number = {5 PART II},
   Pages = {S451},
   Year = {2000},
   Key = {fds234412}
}

@article{fds234413,
   Author = {Richter, W and Warren, WS},
   Title = {Intermolecular multiple quantum coherences in
             liquids},
   Journal = {Concepts in Magnetic Resonance},
   Volume = {12},
   Number = {6},
   Pages = {396-409},
   Year = {2000},
   ISSN = {1043-7347},
   Abstract = {In the early 1990s, the traditional framework of NMR
             spectroscopy was challenged through a series of simple
             experiments. The pulse sequences used consisted of a few RF
             pulses and a few gradient pulses, and the samples were
             mixtures of simple molecules. The spectra showed unexpected
             cross peaks between spins in different molecules. In order
             to explain these results, two basic assumptions had to be
             revisited: (1) the high-temperature approximation to the
             Boltzmann distribution at equilibrium, and (2) the
             cancellation of dipolar couplings in solution. A close look
             at the physics involved showed that correlations between
             spins in separate molecules exist even after a single pulse,
             and that dipolar couplings can make these correlations
             visible in the presence of gradient pulses. A comprehensive
             description of the effect is given here, and some present
             and future applications are discussed. © 2000 lohn Wiley
             &amp; Sons, Inc.},
   Key = {fds234413}
}

@article{fds234414,
   Author = {Tan, H-S and Schreiber, E and Warren, WS},
   Title = {Generation and amplification of shaped ultrafast laser
             pulses, tunable between 500 to 700 nm},
   Journal = {Pacific Rim Conference on Lasers and Electro-Optics, CLEO -
             Technical Digest},
   Pages = {475-},
   Year = {2000},
   Abstract = {If quantum control and spectroscopy is to be applied in
             general to a wide range of atomic or molecular systems,
             methods should be developed to generate shaped optical
             pulses at widely tunable wavelengths to fit the
             corresponding resonance frequency of the various systems
             under study. This article describes and demonstrates such a
             method.},
   Key = {fds234414}
}

@article{fds234415,
   Author = {Goodson, BM and Goswami, D and Rabitz, H and Warren,
             WS},
   Title = {Driving wave packet recurrences with optimally modulated
             laser pulses},
   Journal = {Journal of Chemical Physics},
   Volume = {112},
   Number = {11},
   Pages = {5081-5090},
   Year = {2000},
   Abstract = {In the weak-field limit, laser pulses optimized to induce
             vibrational wave packet recurrences in excited state
             potentials were calculated for Morse oscillators and for a
             real system [the X1Σ+ and A 3II(1) states of IBr]. The
             performance of the optimized pulses was studied via
             simulated wave packet propagation. Such optimal light fields
             may be computationally generated given only the form of the
             electronic potential surfaces, knowledge of the particular
             ground state supplying population, and simple molecular
             constants. Thus it should be possible to use the modulation
             of light fields experimentally optimized to achieve
             recurrences in order to obtain substantial information
             regarding previously uncharacterized potential surfaces in
             both diatomic and polyatomic molecules. Moreover, it should
             be possible to generalize this approach to the strong-field
             limit. © 2000 American Institute of Physics.},
   Key = {fds234415}
}

@article{fds234416,
   Author = {Richter, W and Richter, M and Warren, WS and Merkle, H and Andersen, P and Adriany, G and Ugurbil, K},
   Title = {Functional magnetic resonance imaging with intermolecular
             multiple- quantum coherences},
   Journal = {Magnetic Resonance Imaging},
   Volume = {18},
   Number = {5},
   Pages = {489-494},
   Year = {2000},
   url = {http://dx.doi.org/10.1016/S0730-725X(00)00133-8},
   Abstract = {For the first time, we demonstrate here functional magnetic
             resonance imaging (fMRI) using intermolecular
             multiple-quantum coherences (iMQCs). iMQCs are normally not
             observed in liquid-state NMR because dipolar interactions
             between spins average to zero. If the magnetic isotropy of
             the sample is broken through the use of magnetic field
             gradients, dipolar couplings can reappear, and hence iMQCs
             can be observed. Conventional (BOLD) fMRI measures
             susceptibility variations averaged over each voxel. In the
             experiment performed here, the sensitivity of iMQCs to
             frequency variations over mesoscopic and well-defined
             distances is exploited. We show that iMQC contrast is
             qualitatively and quantitatively different from BOLD
             contrast in a visual stimulation task. While the number of
             activated pixels is smaller in iMQC contrast, the intensity
             change in some pixels exceeds that of BOLD contrast
             severalfold. (C) 2000 Elsevier Science Inc.},
   Doi = {10.1016/S0730-725X(00)00133-8},
   Key = {fds234416}
}

@article{fds234417,
   Author = {Barnes, JP and Warren, WS},
   Title = {Automatic quantum error correction},
   Journal = {Physical Review Letters},
   Volume = {85},
   Number = {4},
   Pages = {856-859},
   Year = {2000},
   url = {http://dx.doi.org/10.1103/PhysRevLett.85.856},
   Abstract = {The ability to engineer the interaction between a bath and a
             system is demonstrated. It is shown that this ability makes
             it possible to implement quantum error correction simply
             through dissipative dynamics, without requiring any external
             manipulation. An example that uses only well-understood
             magnetic interactions is considered to demonstrate the
             potential for a physically realizable implementation of
             automatic quantum error correcting codes.},
   Doi = {10.1103/PhysRevLett.85.856},
   Key = {fds234417}
}

@article{fds234418,
   Author = {Garrett-Roe, S and Warren, WS},
   Title = {Numerical Studies of Intermolecular Multiple Quantum
             Coherences: High-Resolution NMR in Inhomogeneous Fields and
             Contrast Enhancement in MRI},
   Journal = {Journal of Magnetic Resonance},
   Volume = {146},
   Number = {1},
   Pages = {1-13},
   Year = {2000},
   url = {http://dx.doi.org/10.1006/jmre.2000.2096},
   Abstract = {A fast, efficient numerical algorithm is used to study
             intermolecular zero-quantum coherences (iZQCs) and
             double-quantum coherences (iDQCs) in two applications where
             the three-dimensional structure of the magnetization is
             important: high-resolution NMR in inhomogeneous fields and
             contrast enhancement in MRI. Simulations with up to 2
             million coupled volume elements (256 × 256 × 32) show that
             iZQCs can significantly narrow linewidths in the indirectly
             detected dimension of systems with inhomogeneous fields and
             explore the effects of shape and orientation of the
             inhomogeneities. In addition, this study shows that MR
             images from iZQC and iDQC CRAZED pulse sequences contain
             fundamentally new contrast, and a modified CRAZED pulse
             sequence (modCRAZED) can isolate the contrast from
             chemically inequivalent Spins. © 2000 Academic
             Press.},
   Doi = {10.1006/jmre.2000.2096},
   Key = {fds234418}
}

@article{fds234419,
   Author = {Lin, Y-Y and Lisitza, N and Ahn, S and Warren, WS},
   Title = {Resurrection of crushed magnetization and chaotic dynamics
             in solution NMR spectroscopy},
   Journal = {Science},
   Volume = {290},
   Number = {5489},
   Pages = {118-121},
   Year = {2000},
   url = {http://dx.doi.org/10.1126/science.290.5489.118},
   Abstract = {We show experimentally and theoretically that two readily
             observed effects in solution nuclear magnetic resonance
             (NMR) - radiation damping and the dipolar field - combine to
             generate bizarre spin dynamics (including chaotic evolution)
             even with extraordinarily simple sequences. For example,
             seemingly insignificant residual magnetization after a
             crusher gradient triggers exponential regrowth of the
             magnetization, followed by aperiodic turbulent spin motion.
             The estimated Lyapunov exponent suggests the onset of
             spatial-temporal chaos and the existence of chaotic
             attractors. This effect leads to highly irreproducible
             experimental decays that amplify minor nonuniformities such
             as temperature gradients. Imaging applications and
             consequences for other NMR studies are discussed.},
   Doi = {10.1126/science.290.5489.118},
   Key = {fds234419}
}

@article{fds234421,
   Author = {Lin, Y-Y and Ahn, S and Murali, N and Brey, W and Bowers, CR and Warren,
             WS},
   Title = {High-resolution, >1 GHz NMR in unstable magnetic
             fields},
   Journal = {Physical Review Letters},
   Volume = {85},
   Number = {17},
   Pages = {3732-3735},
   Year = {2000},
   url = {http://dx.doi.org/10.1103/PhysRevLett.85.3732},
   Abstract = {Resistive or resistive-superconducting hybrid magnets
             generate spatial homogeneity and temporal stability. As a
             result, these magnets are unacceptable for high-resolution
             experiments. The possibility of effectively homogenizing and
             stabilizing these magnets by spin manipulations that exploit
             intermolecular zero-quantum coherences (iZQCs) is
             demonstrated.},
   Doi = {10.1103/PhysRevLett.85.3732},
   Key = {fds234421}
}

@article{fds234401,
   Author = {Fetterman, MR and Davis, JC and Goswami, D and Yang, W and Warren,
             WS},
   Title = {Propagation of complex laser pulses in optically dense
             media},
   Journal = {Physical Review Letters},
   Volume = {82},
   Number = {20},
   Pages = {3984-3987},
   Year = {1999},
   ISSN = {0031-9007},
   Abstract = {Optically dense rubidium vapor was excited using picosecond
             laser pulses. Effects such as pulse reshaping, self-focusing
             and stimulated emission are observed when shaped laser
             pulses propagated through the rubidium vapor. The pulse
             shapers, sech+, sech- and Gaussian pulses, can control the
             pulse reshaping in the atomic rubidium, thereby exciting the
             atomic system in different fashions.},
   Key = {fds234401}
}

@article{fds234403,
   Author = {Davis, JC and Fetterman, MR and Goswami, D and Yang, WG and Keusters, D and Warren, WS},
   Title = {Altering excitation dynamics in optically dense media using
             shaped ultrafast laser pulses},
   Journal = {IQEC, International Quantum Electronics Conference
             Proceedings},
   Pages = {107-108},
   Year = {1999},
   Abstract = {Shaped pulses are routinely used in various applications to
             alter the excitation dynamics of atoms and molecules. In
             this context, the interaction between intense, shaped
             ultrafast laser pulses and optically dense samples of Rb
             vapor was investigated. Excited state Rb is interesting in
             its own right, as it is a key reagent in the preparation of
             the spin-polarized noble gases that are used in magnetic
             resonance imaging lung studies.},
   Key = {fds234403}
}

@article{fds234404,
   Author = {Davis, JC and Warren, WS},
   Title = {Selective excitation of high vibrational states using Raman
             chirped adiabatic passage},
   Journal = {Journal of Chemical Physics},
   Volume = {110},
   Number = {9},
   Pages = {4229-4237},
   Year = {1999},
   Abstract = {Calculations indicate that high vibrational states of oxygen
             and chlorine can be excited using a series of nonresonant
             Raman pulses, where both the pump and the Stokes pulses are
             chirped with linear frequency sweeps. Most of the previously
             reported coherent processes (such as simple adiabatic
             passage) are seriously degraded when rotational effects are
             included. However, we find that the laser pulse parameters
             (intensity and bandwidth) required to invert population into
             high vibrational states via Raman chirped adiabatic passage
             are achievable using technology that is currently available.
             Applications to homonuclear diatomic molecules are discussed
             in detail. © 1999 American Institute of
             Physics.},
   Key = {fds234404}
}

@article{fds234405,
   Author = {Enss, T and Ahn, S and Warren, WS},
   Title = {Visualizing the dipolar field in solution NMR and MR
             imaging: Three-dimensional structure simulations},
   Journal = {Chemical Physics Letters},
   Volume = {305},
   Number = {1-2},
   Pages = {101-108},
   Year = {1999},
   Abstract = {We propose and demonstrate an efficient numerical approach
             which switches back and forth between real and Fourier
             spaces to handle dipolar field effects for heterogeneous
             three-dimensional structures. Applications to magnetic
             resonance imaging and improving field homogeneity are
             discussed.},
   Key = {fds234405}
}

@article{fds234406,
   Author = {Barnes, JP and Warren, WS},
   Title = {Decoherence and programmable quantum computation},
   Journal = {Physical Review A - Atomic, Molecular, and Optical
             Physics},
   Volume = {60},
   Number = {6},
   Pages = {4363-4374},
   Year = {1999},
   Abstract = {When coherent states of the electromagnetic field are used
             to drive the evolution of a quantum computer, a decoherence
             results due to the back reaction from the qubits onto the
             fields. We show how to calculate this effect. No assumptions
             about the environment are necessary, so this represents a
             useful model to test the fidelity of quantum error
             correcting codes. We examine two cases of interest. First,
             the decoherence from the Walsh-Hadamard transformations in
             Grover's search algorithm is found [Phys. Rev. Lett. 79, 325
             (1997)]. Interference effects, and decoherence-dependent
             phases, are present that could be useful in reducing the
             decoherence. Second, Shor's fault-tolerant controlled-NOT
             gate is examined, utilizing frequency-selective pulses
             [Proceedings, 35th Annual Symposium on Foundations of
             Computer Science (IEEE Press, New York, 1994), pp. 56-65].
             This implementation is found not to be optimal in regards to
             fault-tolerant quantum computation.},
   Key = {fds234406}
}

@article{fds234407,
   Author = {Kimmich, R and Ardelean, I and Lin, Y-Y and Ahn, S and Warren,
             WS},
   Title = {Multiple spin echo generation by gradients of the radio
             frequency amplitude: Two-dimensional nutation spectroscopy
             and multiple rotary echoes},
   Journal = {Journal of Chemical Physics},
   Volume = {111},
   Number = {14},
   Pages = {6501-6509},
   Year = {1999},
   Abstract = {NMR (nuclear magnetic resonance) nutation is treated with
             respect to demagnetizing-field effects on the evolution of
             spin coherences. A two-dimensional NMR nutation spectroscopy
             scheme is suggested consisting of a single radio frequency
             (RF) pulse and a free-evolution period. The RF pulse
             amplitude as well as the external magnetic field are assumed
             to be subject to gradients in the same but otherwise
             arbitrary direction. Cross peaks are predicted as frequency
             domain counterparts of multiple echoes. It is suggested to
             analyze the cross peak shape in terms of distributions of
             internal gradients arising from magnetic susceptibility
             inhomogeneities in heterogeneous samples. Furthermore, a
             pulse scheme solely based on gradients of the RF amplitude
             is treated resulting in the prediction of multiple rotary
             echoes as counterparts to the conventional rotary echo. The
             origin again is evolution in the presence of spatially
             modulated longitudinal magnetization in the tilted rotating
             frame. © 1999 American Institute of Physics.},
   Key = {fds234407}
}

@article{fds234408,
   Author = {Keusters, D and Tan, H-S and Warren, WS},
   Title = {Role of pulse phase and direction in two-dimensional optical
             spectroscopy},
   Journal = {The Journal of Physical Chemistry Part A: Molecules,
             Spectroscopy, Kinetics, Environment and General
             Theory},
   Volume = {103},
   Number = {49},
   Pages = {10369-10380},
   Year = {1999},
   ISSN = {1089-5639},
   Abstract = {This paper examines the parallels between magnetic resonance
             and optical spectroscopy, with the goal of determining to
             what extent the benefits of 2DNMR might be extended into the
             optical regime. Precise optical analogues of the simplest
             2DNMR sequences (collinear pulse sequences with phased laser
             pulse generation, phase sensitive detection, and phase
             cycling) are now feasible, and we demonstrate that they do
             generate cross-peaks which reveal common energy levels, even
             when averaged over the distribution of pulse flip angles
             expected in most optical experiments. One enormous
             difference between laser and NMR experiments-the use of
             pulses in different directions in optics-can be exploited to
             eliminate much of the phase cycling required in NMR. Phase
             control does permit rotating-frame detection, which is
             likely to be a substantial practical advantage. Finally, we
             point out optical analogues of the simplest 2DNMR sequences
             (COSY and NOESY) will likely add little to our understanding
             of ultrafast dynamics. Optical analogues of more complex 2D
             sequences, combining phase control for selective refocusing
             with noncollinear pulse generation for coherence pathway
             selection, show more promise. © 1999 American Chemical
             Society.},
   Key = {fds234408}
}

@article{fds234409,
   Author = {Yang, W and Huang, F and Fetterman, MR and Davis, JC and Goswami, D and Warren, WS},
   Title = {Real-time adaptive amplitude feedback in an AOM-based
             ultrafast optical pulse shaping system},
   Journal = {IEEE Photonics Technology Letters},
   Volume = {11},
   Number = {12},
   Pages = {1665-1667},
   Year = {1999},
   url = {http://dx.doi.org/10.1109/68.806881},
   Abstract = {We demonstrate real-time adaptive amplitude feedback in an
             AOM-based ultrafast optical pulse shaping system operating
             at λ = 1550 nm wavelength for optical communication
             applications. At the optimized feedback depth, a simple
             negative feedback algorithm converges in fewer than 10
             iterations to within 5% of the target shape. This technique
             may be very useful for many applications including
             spectrum-sliced WDM.},
   Doi = {10.1109/68.806881},
   Key = {fds234409}
}

@article{fds234400,
   Author = {Yang, W and Keusters, D and Goswami, D and Warren,
             WS},
   Title = {Rapid ultrafine-tunable optical delay line at the 1.55-μm
             wavelength},
   Journal = {Optics Letters},
   Volume = {23},
   Number = {23},
   Pages = {1843-1845},
   Year = {1998},
   Abstract = {A fast, ultrafine-tunable delay line at 1550 nm is
             demonstrated by use of acousto-optic pulse shaping. Delays
             of up to 30 ps can be achieved without any optical
             readjustment. The delay is linear to the rf center frequency
             applied to the acousto-optic modulator and is fully
             electronic. It takes only 3 μm to switch between different
             time slots, irrespective of the time separation in the
             tuning range of 30 ps; for a smaller tuning range the tuning
             speed can be faster. The tuning resolution and range depend
             on the choice of system parameters. The pulse energy can be
             regulated by rf power. © 1998 Optical Society of
             America.},
   Key = {fds234400}
}

@article{fds234402,
   Author = {Ahn, S and Lee, S and Warren, WS},
   Title = {The competition between intramolecular J couplings,
             radiation damping, and intermolecular dipolar couplings in
             two-dimensional solution nuclear magnetic
             resonance},
   Journal = {Molecular Physics},
   Volume = {95},
   Number = {5},
   Pages = {769-785},
   Year = {1998},
   Abstract = {Scalar couplings have long been used to observe forbidden
             transitions indirectly, e.g., the multiple-quantum
             transitions detected frequently in the indirect dimension of
             multidimensional NMR experiments. Recent work has shown that
             intermolecular dipolar couplings in solution will also
             permit the detection of multiple-quantum coherences, this
             time between separated spins (intermolecular
             multiple-quantum coherences, iMQCs). Analytical expressions
             are derived to describe spin evolution for an essentially
             arbitrarily complex coupled spin system when dipolar
             couplings or radiation damping also are significant. The
             results are tested on an A2B3+Cn system (methyl ethyl
             ketone). iMQCs that are forbidden from radiation damping or
             dipolar couplings alone can become allowed in the presence
             of J couplings, but the multiplet patterns differ
             dramatically from conventional multiplets. Scalar couplings
             open up new pathways for pumping the normally allowed
             transitions.},
   Key = {fds234402}
}

@article{fds234583,
   Author = {Wilson, KR and Bardeen, CJ and Brakenhoff, GJ and Buist, A and Cao, J and Carpenter, SD and Che, J and Squier, JA and Warren, WS and Weber, PM and Yakovlev, VV},
   Title = {New tricks in quantum control},
   Journal = {Technical Digest - European Quantum Electronics
             Conference},
   Pages = {3-},
   Year = {1998},
   Abstract = {Quantum control involving multiple interactions with light
             of different colors within the same light pulse is analyzed.
             Experiments on I2 have demonstrated up to a 300% enhancement
             of the multiphoton yield with the appropriately chirped
             pulse. Such multiphoton control can be the basis of the
             molecular `π pulse,' capable of inverting the entire
             electronic ground state population of a molecule to an
             excited electronic state. This multiphoton quantum control
             is applied to produce a new class of molecular reporter
             system for ultrafast measurement of the molecular scale
             chemical environment, and is used to measure the pH from the
             fluorescence intensity ratio for positive and negative
             chirped pulses.},
   Key = {fds234583}
}

@article{fds234584,
   Author = {Wilson, KR and Bardeen, C and Barty, CPJ and Brakenhoff, GJ and Buist,
             AH and Cao, J and Carpenter, SD and Che, J and Fittinghoff, DN and Müller,
             M and Squier, JA and Warren, WS and Weber, PM and Yakovlev,
             VV},
   Title = {New ways to observe and control dynamics},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {3273},
   Pages = {214-218},
   Year = {1998},
   url = {http://dx.doi.org/10.1117/12.306130},
   Abstract = {We summarize recent progress aimed at observing biochemical
             and biological dynamics using confocal microscopy with 3D
             spatial resolution down to a few hundred nm and temporal
             resolution to 15 fs. We also review recent control of
             population dynamics using tailored ultrafast pulses, i.e.
             quantum control. Progress is described for i) feedback
             control, ii) multiphoton control, and iii) molecular π
             pulse. Finally, using ultrafast light pulses, we combine
             confocal and quantum control techniques to produce a new way
             to measure the microscopic chemical environment, in this
             case pH, potentially with a spatial resolution of a few
             hundred nanometers.},
   Doi = {10.1117/12.306130},
   Key = {fds234584}
}

@article{fds234585,
   Author = {Yang, W and Davis, J and Goswami, D and Fetterman, M and Warren,
             WS},
   Title = {Optical wavelength domain code-division multiplexing using
             an AOM-based ultrafast optical pulse shaping
             approach},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {3531},
   Pages = {80-86},
   Year = {1998},
   Abstract = {Optical wavelength domain code-division multiplexing access
             (WD-CDMA) using an AOM-based ultrafast optical pulse shaping
             approach is proposed and demonstrated experimentally at 1550
             nm. This new multiplexing technique utilizes wavelength
             domain codes that are essentially different optical spectral
             patterns in order to achieve CDMA. In addition to the
             advantages of the conventional CDMA technique, WD-CDMA can
             make full use of the entire optical bandwidth without
             requiring faster optical switches or modulators. This
             approach also drastically reduces sensitivity to fiber
             dispersion. Experimentally, we demonstrate an optical
             spectral encoder using ultrafast optical pulse shaping with
             16 wavelength bits over an optical bandwidth of 5 THz. The
             spectrally-encoded optical pulse generated with the spectral
             encoder is then decoded with different WD-CDMA codes in the
             spectral domain. Different code-division channels can thus
             extract their own bit information while sharing the same
             spectral-encoded laser pulse as their common carrier. These
             spectral-encoded pulses are shown using the
             cross-correlation technique to be confined within a time
             slot of 15 ps. A larger number of WD bits is also achievable
             with our system.},
   Key = {fds234585}
}

@article{fds234586,
   Author = {Warren, WS and Ahn, S},
   Title = {The boundary between liquidlike and solidlike behavior in
             magnetic resonance},
   Journal = {Journal of Chemical Physics},
   Volume = {108},
   Number = {4},
   Pages = {1313-1325},
   Year = {1998},
   Abstract = {Recent experimental work in two-dimensional solution NMR
             (nuclear magnetic resonance) has demonstrated anomalous
             cross-peaks and additional resonances due to dipolar
             couplings between distant nuclei. These spectra have been
             analyzed either classically, using Bloch equations which
             include a mean-field approximation to the demagnetizing
             field, or quantum mechanically, using a full density matrix
             picture which shows that the peaks correspond to
             intermolecular multiple-quantum coherences (iMQCs). Here we
             use a density matrix treatment to predict intensities in
             solution for dipolar effects conventionally seen in solids;
             we also explore in detail the fundamental differences
             between dipolar effects in solids and liquids. For example,
             even though polarization transfer via the dipolar
             Hamiltonian in solution is not possible, indirect detection
             with substantial signal enhancement is possible. We find
             that, even for high-γ nuclei such as 1H or 3He, solidlike
             dipolar effects are quite small unless the diffusion
             constant is roughly one million times smaller than that of
             water - which means that deviations between the quantum and
             classical treatments are barely observable in solution NMR,
             and that even solid 3He has liquidlike dipolar effects in
             agreement with experiment. However, the dipolar correlation
             function has an extremely unusual functional form - the long
             time falloff is proportional to t-3/2, not the exponential
             one commonly encounters. Because of this long falloff,
             solidlike dipolar effects can be substantial in solution
             electron spin resonance, and the classical picture of the
             demagnetizing field would fail in that case. © 1998
             American Institute of Physics.},
   Key = {fds234586}
}

@article{fds234587,
   Author = {Fetterman, M and Goswami, D and Keusters, D and Rhee, J-K and Warren,
             WS},
   Title = {Generation of amplified shaped pulses for highly adiabatic
             excitation},
   Journal = {Springer Series in Chemical Physics},
   Volume = {63},
   Pages = {24-26},
   Year = {1998},
   ISSN = {0172-6218},
   Abstract = {Complex amplified pulses, including a 1 ps, 100 μJ
             tanh-swept sech pulse for adiabatic inversion, are generated
             experimentally. STRUT detection verifies the modulation and
             follows the dynamics induced by such pulses in Rb vapor.
             Applications to production of spin-polarized gases for
             medical imaging are discussed.},
   Key = {fds234587}
}

@article{fds234588,
   Author = {Bardeen, C and Yakovlev, VV and Wilson, KR and Carpenter, SD and Weber,
             PM and Warren, WS},
   Title = {Feedback quantum control of population transfer using shaped
             femtosecond pulses},
   Journal = {Springer Series in Chemical Physics},
   Volume = {63},
   Pages = {645-647},
   Year = {1998},
   ISSN = {0172-6218},
   Abstract = {Quantum control is extended to complex molecular systems by
             using experimental feedback to control the acousto-optic
             tailoring of ultrashort pulses.},
   Key = {fds234588}
}

@article{fds234589,
   Author = {Warren, WS and Goswami, D and Mayr, S},
   Title = {Laser enhanced NMR spectroscopy, revisited},
   Journal = {Molecular Physics},
   Volume = {93},
   Number = {3},
   Pages = {371-375},
   Year = {1998},
   Abstract = {Experimental investigations of the effects of moderately
             powerful (10-20 W cm-2) off-resonant continuous lasers on
             NMR spectra provide no evidence for the B(3) field recently
             proposed, or for any other mechanism which depends on the
             light polarization. Observed 1H and 13C line shifts with
             argon-ion laser irradiation for the molecule
             p-methoxyphenyliminocamphor mostly can be explained by
             heating effects. Residual shifts due to other mechanisms
             appear to be at most 0·1 Hz (5% of the linewidth). One
             mechanism which could account for residual shifts of this
             magnitude is differences between NMR frequencies in the
             excited (triplet) and ground electronic states, although our
             data have insufficient resolution to make definitive claims.
             However, it seems unlikely that this effect can be made
             sufficiently large to give practical resolution enhancements
             without massive heating.},
   Key = {fds234589}
}

@article{fds234590,
   Author = {Warren, WS},
   Title = {Rethinking solution NMR},
   Journal = {Science},
   Volume = {280},
   Number = {5362},
   Pages = {398-399},
   Year = {1998},
   url = {http://dx.doi.org/10.1126/science.280.5362.398},
   Doi = {10.1126/science.280.5362.398},
   Key = {fds234590}
}

@article{fds234591,
   Author = {Ahn, S and Warren, WS},
   Title = {Effects of intermolecular dipolar couplings in solution NMR
             in separated time intervals: The competition for coherence
             transfer pathways},
   Journal = {Chemical Physics Letters},
   Volume = {291},
   Number = {1-2},
   Pages = {121-129},
   Year = {1998},
   Abstract = {We investigate the competition between intermolecular
             dipolar effects in multiple time intervals and develop a
             theoretical framework to understand coherence transfer when
             this competition is important. The quantum picture permits
             explicit evaluation of coherence transfer pathways, which
             have been verified by experimental data obtained from pulse
             sequences with multiple-quantum selective phase cycling.
             Implications for sequences in common use in biological
             applications are discussed.},
   Key = {fds234591}
}

@article{fds234592,
   Author = {Ahn, S and Lisitza, N and Warren, WS},
   Title = {Intermolecular Zero-Quantum Coherences of Multi-component
             Spin Systems in Solution NMR},
   Journal = {Journal of Magnetic Resonance},
   Volume = {133},
   Number = {2},
   Pages = {266-272},
   Year = {1998},
   Abstract = {Intermolecular zero-quantum coherences (iZQC) induced by the
             dipolar demagnetizing field can give both P- and N-type
             cross peaks. This paper shows that the relative intensities
             of the two types of iZQC peaks follow a simple relation,
             tan2 (θ/2), from both the quantum (spin density matrix) and
             classical (modified Bloch equation) calculations. The
             experimental data and numerical simulations agree well with
             the prediction. In addition, higher-order iZQCs are
             experimentally examined for the first time and are explained
             by the quantum picture in which dipolar couplings convert
             four-spin operators into observable magnetization. © 1998
             Academic Press.},
   Key = {fds234592}
}

@article{fds234593,
   Author = {Fetterman, MR and Goswami, D and Keusters, D and Yang, W and Warren,
             WS},
   Title = {Ultrafast pulse shaping: Amplification and
             characterization},
   Journal = {Optics express},
   Volume = {3},
   Number = {10},
   Pages = {366-375},
   Year = {1998},
   ISSN = {1094-4087},
   Abstract = {We demonstrate high-resolution amplified pulse shaping using
             an acousto-optic modulator (AOM) at a center-wavelength of
             795nm. The output pulses have energy of 200μJ/pulse and a
             transform-limited pulsewidth of 150fs. A spectral modulation
             of over 40 features is achieved in a single pulse. We
             characterize the pulses using the STRUT (Spectrally and
             Temporally Resolved Upconversion Technique). Using
             predistortion techniques, we demonstrate that the pulses can
             be shaped in amplitude and phase. We create a complex pulse
             shape with hyperbolic secant amplitude and hyperbolic
             tangent frequency sweep, which is useful for applications in
             adiabatic rapid passage experiments. © 1998 Optical Society
             of America.},
   Key = {fds234593}
}

@article{fds234576,
   Author = {Warren, WS and Gershenfeld, N and Chuang, I},
   Title = {The usefulness of NMR quantum computing},
   Journal = {Science},
   Volume = {277},
   Number = {5332},
   Pages = {1688-1690},
   Year = {1997},
   url = {http://dx.doi.org/10.1126/science.277.5332.1688},
   Doi = {10.1126/science.277.5332.1688},
   Key = {fds234576}
}

@article{fds234577,
   Author = {Kobayashi, H and Prucnal, PR and Warren, WS},
   Title = {A terabit-per-second network with the spectral-domain
             modulation},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {3231},
   Pages = {75-86},
   Year = {1997},
   ISSN = {0277-786X},
   url = {http://dx.doi.org/10.1117/12.290449},
   Abstract = {We discuss an architecture and underlying technologies of
             terabit-per-second network with the spectral-domain
             modulation. The baseline architecture is TDM which exploits
             our techniques for imposing &gt; 1000 pixel phase and
             amplitude modulation on the spectrum of a 100 fs laser
             pulse, using microsecond radiofrequency pulse trains, for
             all-optical demultiplexing to efficiently select 100 fs-100
             ps time slices. The network architectures we will initially
             explore is a single-hop star network that uses an active
             star coupler as a shared medium. We will also explore a
             WDM/TDM network with a waveguide grating router as its
             hub.},
   Doi = {10.1117/12.290449},
   Key = {fds234577}
}

@article{fds234578,
   Author = {Tull, JX and Dugan, MA and Warren, WS},
   Title = {High-resolution, ultrafast laser pulse shaping and its
             applications},
   Journal = {Advances in Magnetic and Optical Resonance},
   Volume = {20},
   Number = {C},
   Pages = {1-II},
   Year = {1997},
   ISSN = {1057-2732},
   url = {http://dx.doi.org/10.1016/S1057-2732(97)80002-2},
   Doi = {10.1016/S1057-2732(97)80002-2},
   Key = {fds234578}
}

@article{fds234579,
   Author = {Dugan, MA and Tull, JX and Warren, WS},
   Title = {High-resolution acousto-optic shaping of unamplified and
             amplified femtosecond laser pulses},
   Journal = {Journal of the Optical Society of America
             B},
   Volume = {14},
   Number = {9},
   Pages = {2348-2358},
   Year = {1997},
   ISSN = {0740-3224},
   Abstract = {We focus theoretically and experimentally on the fundamental
             limitations of spectral pulse shaping using an acousto-optic
             modulator. We analyze the role of the relative thickness of
             the interaction region as dictated by the acousto-optic Q
             parameter and show that varying Q allows flexibility in
             choosing between diffraction efficiency and pixels of
             resolution. We model and experimentally demonstrate the
             effects of potential nonidealities such as nonlinear
             acoustic attenuation. In addition, we derive a simple and
             intuitive expression to predict the magnitude of the
             distortions in the spatial profile generated by an
             acousto-optic-modulator spectral light modulator. Finally,
             we demonstrate amplification of acousto-optic-modulator-generated
             shaped pulses for the first time. © 1997 Optical Society of
             America.},
   Key = {fds234579}
}

@article{fds234580,
   Author = {Bardeen, CJ and Yakovlev, VV and Wilson, KR and Carpenter, SD and Weber,
             PM and Warren, WS},
   Title = {Feedback quantum control of molecular electronic population
             transfer},
   Journal = {Chemical Physics Letters},
   Volume = {280},
   Number = {1-2},
   Pages = {151-158},
   Year = {1997},
   Abstract = {Feedback quantum control, where the sample 'teaches' a
             computer-controlled arbitrary lightform generator to find
             the optimal light field, is experimentally demonstrated for
             a molecular system. Femtosecond pulses tailored by a
             computer-controlled acousto-optic pulse shaper excite
             fluorescence from laser dye molecules in solution.
             Fluorescence and laser power are monitored, and the computer
             uses the experimental data and a genetic algorithm to
             optimize population transfer from ground to first excited
             state. Both efficiency (the ratio of excited state
             population to laser energy) and effectiveness (total excited
             state population) are optimized. Potential use as an
             'automated theory tester' is discussed.},
   Key = {fds234580}
}

@article{fds234581,
   Author = {Ahn, S and Warren, WS and Lee, S},
   Title = {Quantum Treatment of Intermolecular Multiple-Quantum
             Coherences with Intramolecular J Coupling in Solution
             NMR},
   Journal = {Journal of Magnetic Resonance},
   Volume = {128},
   Number = {2},
   Pages = {114-129},
   Year = {1997},
   Abstract = {A recently introduced density matrix picture for dipolar
             effects in solution NMR (1996, J. Chem. Phys. 105, 874) gave
             complete solutions for intermolecular multiple-quantum
             coherences for single-component samples without scalar
             couplings. This paper, for the first time, shows that this
             quantum picture can lead to explicit signal expressions for
             multicomponent samples of molecules with internal scalar
             couplings (here assumed to generate a first-order spectrum)
             and long-range dipolar couplings. Experimental observation
             of a triplet in the indirectly detected dimension for a
             heteronuclear CRAZED sequence (13CHCl3 sample, ZQ or 2Q
             coherences) gives clear evidence that the coupling is due to
             the intermolecular dipolar coupling. We also make
             comparisons with classical pictures which introduce the
             dipolar demagnetization field in multicomponent spin
             systems. © 1997 Academic Press.},
   Key = {fds234581}
}

@article{fds234582,
   Author = {Rhee, J-K and Kobayashi, H and Warren, WS},
   Title = {Optical frequency domain differential phase shift keying in
             femtosecond-pulse spectral modulation systems},
   Journal = {Journal of Lightwave Technology},
   Volume = {15},
   Number = {12},
   Pages = {2214-2222},
   Year = {1997},
   ISSN = {0733-8724},
   url = {http://dx.doi.org/10.1109/50.643543},
   Abstract = {We propose a novel scheme of differential phase shift keying
             (DPSK) in the optical frequency domain. We take advantage of
             the intrinsic coherence among spectral elements derived by
             spectrum slicing a femtosecond optical pulse, introducing
             differential phase modulation between adjacent spectral
             elements with a femtosecond-pulse shaper. Detection of the
             differential phase is achieved by a Mach-Zehnder (MZ) or
             Sagnac interferometric receiver without requirement of any
             external phase reference.},
   Doi = {10.1109/50.643543},
   Key = {fds234582}
}

@article{fds234571,
   Author = {Dugan, M and Tull, JX and Ree, J-K and Warren, WS},
   Title = {High-resolution ultrafast laser pulse shaping for quantum
             control and terabit per second communications},
   Journal = {Springer Series in Chemical Physics},
   Volume = {62},
   Pages = {26-27},
   Year = {1996},
   ISSN = {0172-6218},
   Abstract = {High resolution (≈ 1000 pixels), rapidly updatable fs
             laser pulse shaping permits a terabit per second
             communications architecture and quantum control.},
   Key = {fds234571}
}

@article{fds234572,
   Author = {Bachiller, PR and Ahn, S and Warren, WS},
   Title = {Detection of intermolecular heteronuclear multiple-quantum
             coherences in solution NMR},
   Journal = {Journal of Magnetic Resonance - Series A},
   Volume = {122},
   Number = {1},
   Pages = {94-99},
   Year = {1996},
   ISSN = {1064-1858},
   Key = {fds234572}
}

@article{fds234573,
   Author = {Mattiello, DL and Warren, WS and Mueller, L and II,
             BTF},
   Title = {Minimizing the water resonance in biological NMR:
             Characterization and suppression of intermolecular dipolar
             interactions by multiple-axis gradients},
   Journal = {Journal of the American Chemical Society},
   Volume = {118},
   Number = {13},
   Pages = {3253-3261},
   Year = {1996},
   url = {http://dx.doi.org/10.1021/ja953186o},
   Abstract = {Anomalous crosspeaks and additional resonances in the
             indirectly detected dimension have been previously observed
             in a number of 2D NMR experiments applied to samples having
             at least one concentrated species. These unexpected peaks
             exhibit all the characteristics of intermolecular
             multiple-quantum coherences. Since these coherences are
             possible within the concentrated species alone, their
             creation and subsequent detection may be one of the causes
             for poor water suppression in a variety of biomolecular NMR
             experiments, e.g., the conventional MQ-filtered-(MQF) and
             MQ-COSY experiments applied to proteins/peptides in 90%
             water. In this report, we experimentally characterize the
             creation/observation of intermolecular water-water MQ
             coherences using variable-angle pulsed field gradients. We
             show that the existing theoretical picture is consistent
             with all of our experimental observations, thereby
             validating the predictive power of the intuition gained from
             this picture. We also provide an increased understanding of
             the effect that variable-angle gradients can have on the
             intensity of observable magnetization arising from these
             intermolecular MQ coherences. Finally, we establish a basis
             on which one may reasonably speculate concerning the impact
             of these coherences on water suppression within the
             repertoire of gradient-enhanced heteronuclear experiments
             that are currently being applied to 13C/15N isotopically
             labeled proteins in 90% water.},
   Doi = {10.1021/ja953186o},
   Key = {fds234573}
}

@article{fds234574,
   Author = {Vathyam, S and Lee, S and Warren, WS},
   Title = {Homogeneous NMR spectra in inhomogeneous
             fields},
   Journal = {Science},
   Volume = {272},
   Number = {5258},
   Pages = {92-96},
   Year = {1996},
   Abstract = {Researchers interested in high-resolution nuclear magnetic
             resonance (NMR) spectroscopy have long sought higher
             magnetic fields to enhance resolution and simplify spectra.
             Magnets with substantially larger fields than those
             available in the best commercial spectrometers are
             available, but the inhomogeneity is unacceptable for
             high-resolution spectra. A detection method (termed
             HOMOGENIZED) is presented that removes inhomogeneity while
             retaining chemical shift differences and J couplings. With
             existing inhomogeneous magnets, this method could nearly
             doublethe largest resonance frequency available for
             high-resolution NMR. The HOMOGENIZED sequence is based on
             observations of intermolecular zero-quantum coherences
             between a solute molecule and solvent molecules that are
             micrometers away; as long as the field is homogeneous over
             this short distance, sharp resonances are recovered without
             echoes. Experimental demonstrations and a detailed density
             matrix theory to explain the effect are presented.},
   Key = {fds234574}
}

@article{fds234575,
   Author = {Lee, S and Richter, W and Vathyam, S and Warren, WS},
   Title = {Quantum treatment of the effects of dipole-dipole
             interactions in liquid nuclear magnetic resonance},
   Journal = {Journal of Chemical Physics},
   Volume = {105},
   Number = {3},
   Pages = {874-900},
   Year = {1996},
   Abstract = {Experimental observation of anomalous intermolecular
             cross-peaks in two-dimensional solution NMR spectra have
             attracted significant recent attention. Extremely simple
             pulse sequences on extremely simple samples with large
             equilibrium magnetization give resonances in the indirectly
             detected dimension which are simply impossible in the
             conventional density matrix framework of NMR. Here we extend
             a recently proposed density matrix treatment [Science 262,
             2005 (1993)] to calculate the exact time evolution for a
             variety of pulse sequences. This density matrix treatment
             explicitly removes two fundamental assumptions of the
             standard theory - it includes the dipolar interaction
             between spins in solution (which is only partially averaged
             away by diffusion) and completely removes the high
             temperature approximation to the equilibrium density matrix
             [exp(-βℋ)≈1-βℋ]. We compare this quantum mechanical
             treatment to a corrected classical model, which modifies the
             dipolar demagnetizing field formulation to account for the
             effects of residual magnetization, and show that the quantum
             picture can be reduced to this corrected classical model
             when certain assumptions about the retained dipolar
             couplings are valid. The combination of quantum and
             classical pictures provides enormously better predictive
             power and computational convenience than either technique
             alone. © 1996 American Institute of Physics.},
   Key = {fds234575}
}

@article{fds234396,
   Author = {Melinger, JS and McMorrow, D and Hillegas, C and Warren,
             WS},
   Title = {Selective excitation of vibrational overtones in an
             anharmonic ladder with frequency- and amplitude-modulated
             laser pulses},
   Journal = {Physical Review A - Atomic, Molecular, and Optical
             Physics},
   Volume = {51},
   Number = {4},
   Pages = {3366-3369},
   Year = {1995},
   ISSN = {1050-2947},
   url = {http://dx.doi.org/10.1103/PhysRevA.51.3366},
   Abstract = {We show numerically that the complex hyperbolic secant pulse
             provides robust selective inversion of vibrational
             overtones. A density-matrix analysis is performed for a
             ten-level Morse-oscillator approximation of a diatomic
             molecule. We also show that in the limit of adiabatic
             excitation the complex-hyperbolic-secant pulse yields an
             inversion spectrum that is narrower than its spectral
             bandwidth. © 1995 The American Physical
             Society.},
   Doi = {10.1103/PhysRevA.51.3366},
   Key = {fds234396}
}

@article{fds234397,
   Author = {Melinger, JS and Gandhi, SR and Hariharan, A and Goswami, D and Warren,
             WS},
   Title = {Erratum: Adiabatic population transfer with frequency swept
             laser pulses (The Journal of Chemical Physics (1994) 101
             (6439))},
   Journal = {Journal of Chemical Physics},
   Volume = {102},
   Number = {13},
   Pages = {5574-},
   Year = {1995},
   ISSN = {0021-9606},
   Key = {fds234397}
}

@article{fds234398,
   Author = {Richter, W and Lee, S and Warren, WS and He, Q},
   Title = {Imaging with intermolecular multiple-quantum coherences in
             solution nuclear magnetic resonance},
   Journal = {Science},
   Volume = {267},
   Number = {5198},
   Pages = {654-657},
   Year = {1995},
   Abstract = {A magnetic resonance imaging technique based on
             intermolecular multiple-quantum coherences in solution (the
             correlated spectroscopy revamped by asymmetric z gradient
             echo detection or CRAZED experiment) is described here.
             Correlations between spins in different molecules were
             detected by magnetic-field gradient pulses. In order for a
             correlation to yield an observable signal, the separation
             between the two spins must be within a narrow band that
             depends on the area of the gradient pulses. The separation
             can be tuned from less than 10 micrometers to more than 1
             millimeter, a convenient range for many applications.},
   Key = {fds234398}
}

@article{fds234399,
   Author = {Warren, WS and Lee, S and Richter, W and Vathyam,
             S},
   Title = {Correcting the classical dipolar demagnetizing field in
             solution NMR},
   Journal = {Chemical Physics Letters},
   Volume = {247},
   Number = {3},
   Pages = {207-214},
   Year = {1995},
   ISSN = {0009-2614},
   url = {http://dx.doi.org/10.1016/0009-2614(95)01184-5},
   Abstract = {Numerous observations of anomalous intermolecular
             multiple-quantum and cross correlation peaks in solution NMR
             have led to a variety of theoretical treatments, some
             involving radiation damping or modified classical Bloch
             equations, others involving full quantum mechanical
             derivations. We explore the theoretical underpinnings of the
             classical model, which invokes the dipolar demagnetizing
             field, and correct a significant omission in the original
             formulation which has been propagated in later papers. This
             correction gives good agreement between theory and
             experiment. © 1995.},
   Doi = {10.1016/0009-2614(95)01184-5},
   Key = {fds234399}
}

@article{fds234392,
   Author = {Goswami, D and Warren, WS},
   Title = {Effects of pulses with simple phase and frequency
             modulations},
   Journal = {Physical Review A - Atomic, Molecular, and Optical
             Physics},
   Volume = {50},
   Number = {6},
   Pages = {5190-5196},
   Year = {1994},
   ISSN = {1050-2947},
   url = {http://dx.doi.org/10.1103/PhysRevA.50.5190},
   Abstract = {The effects of pulse shapes with simple phase and frequency
             modulation (phase proportional to amplitude or intensity,
             frequency proportional to intensity) are explored
             numerically. Many such shapes can be generated by combining
             self-phase-modulation with modern laser pulse-shaping
             capabilities (which are more flexible for amplitude
             modulation than for frequency modulation). Even though all
             of these wave forms begin and end at the same frequency (and
             hence violate the mathematical conditions for adiabatic
             inversion), we show that they can generate adiabatic
             population inversion or suppress intramolecular energy
             redistribution. © 1994 The American Physical
             Society.},
   Doi = {10.1103/PhysRevA.50.5190},
   Key = {fds234392}
}

@article{fds234394,
   Author = {Melinger, JS and Gandhi, SR and Hariharan, A and Goswami, D and Warren,
             WS},
   Title = {Adiabatic population transfer with frequency-swept laser
             pulses},
   Journal = {Journal of Chemical Physics},
   Volume = {101},
   Number = {8},
   Pages = {6439-6454},
   Year = {1994},
   url = {http://dx.doi.org/10.1063/1.468368},
   Abstract = {The application of frequency-swept picosecond laser pulses
             in achieving efficient population transfer via adiabatic
             rapid passage (ARP) was described. The basic theoretical
             considerations useful for understanding ARP in both
             few-level and multi-level systems were presented. A detailed
             report of the experimental arrangement and methods used to
             generate frequency-swept laser pulses was also provided. The
             results of coherent population transfer experiments on solid
             phase and vapor phase systems were presented and compared to
             theoretical calculations on model systems. It was determined
             that the frequency sweep of the laser pulse need not
             necessarily be linear, nor even monotonic. Selective
             excitation and enhanced population will surely occur
             provided the conditions for ARP are well
             satisfied.},
   Doi = {10.1063/1.468368},
   Key = {fds234394}
}

@article{fds234395,
   Author = {Hillegas, CW and Tull, JX and Goswami, D and Strickland, D and Warren,
             WS},
   Title = {Femtosecond laser pulse shaping by use of microsecond
             radio-frequency pulses},
   Journal = {Optics Letters},
   Volume = {19},
   Number = {10},
   Pages = {737-739},
   Year = {1994},
   Abstract = {In this paper, a method for modulating femtosecond pulses
             was presented, using microsecond rf pulses in an
             acousto-optic modulator (AOM). It was demonstrated that an
             AOM at the line focus of a zero-dispersion grating pair
             furnished convenient and powerful capabilities for
             femtosecond pulse shaping. In comparison with current
             methods, this approach has the advantages of faster update
             times, no pixel gaps, high isolation, and simple
             calibration. It was also better suited for application with
             existing commercial components. Experimental data were
             provided that exhibited effective modulation and discussed
             the possible ultimate capacities and limitations.},
   Key = {fds234395}
}

@article{fds234385,
   Author = {Goswami, D and Warren, WS},
   Title = {Control of chemical dynamics by restricting intramolecular
             vibrational relaxation},
   Journal = {Journal of Chemical Physics},
   Volume = {99},
   Number = {6},
   Pages = {4509-4517},
   Year = {1993},
   ISSN = {0021-9606},
   Abstract = {We address the issue of localization of bond energy in a
             molecule by stopping intramolecular vibrational relaxation
             (IVR). We show through model calculations that appropriate
             frequency sweeps permit selective locking over a
             well-defined range of resonance frequencies, with little
             excitation outside that range. We also propose a modified
             version of an adiabatic half passage experiment that will
             perform photon locking without complications from
             inhomogeneities or partial excitation of other transitions
             for a bright state coupled to a finite number of dark
             states. © 1993 American Institute of Physics.},
   Key = {fds234385}
}

@article{fds234386,
   Author = {Melinger, JS and Hariharan, A and Gandhi, SR and Warren,
             WS},
   Title = {Stimulated emission pumping and selective excitation by
             adiabatic passage with frequency-modulated picosecond laser
             pulses},
   Journal = {Springer Series in Chemical Physics},
   Number = {55},
   Pages = {113-115},
   Year = {1993},
   Abstract = {We demonstrate that picosecond frequency modulated laser
             pulses produce more efficient population transfer, and more
             selective excitation than equivalent (same spectral width)
             nearly transform limited laser pulses. We also note the ″
             robustness″, or insensitivity of the properties of the
             material excitation to the parameters of the laser field,
             that is inherent to the adiabatic process. The robustness
             obtainable by adiabatic passage may ultimately prove useful
             to laboratory applications of theoretical schemes for
             laser-control of chemical reaction dynamics.},
   Key = {fds234386}
}

@article{fds234387,
   Author = {Harris, RA and Jr, IT and Warren, WS and Mayr, S and Goswami, D and Jr,
             APW},
   Title = {Laser-enhanced NMR spectroscopy: Theoretical
             considerations},
   Journal = {Science},
   Volume = {259},
   Number = {5096},
   Pages = {835-836},
   Year = {1993},
   Key = {fds234387}
}

@article{fds234388,
   Author = {Warren, WS},
   Title = {Chemistry with photons},
   Journal = {Science},
   Volume = {262},
   Number = {5136},
   Pages = {1008-1009},
   Year = {1993},
   Key = {fds234388}
}

@article{fds234389,
   Author = {Warren, WS and Mayr, S and Goswami, D and Jr, APW},
   Title = {Laser-enhanced NMR spectroscopy: Theoretical
             considerations},
   Journal = {Science},
   Volume = {259},
   Number = {5096},
   Pages = {836-},
   Year = {1993},
   ISSN = {0036-8075},
   Key = {fds234389}
}

@article{fds234390,
   Author = {He, Q and Richter, W and Vathyam, S and Warren, WS},
   Title = {Intermolecular multiple-quantum coherences and cross
             correlations in solution nuclear magnetic
             resonance},
   Journal = {Journal of Chemical Physics},
   Volume = {98},
   Number = {9},
   Pages = {6779-6800},
   Year = {1993},
   ISSN = {0021-9606},
   Abstract = {It was recently reported that multiple-quantum NMR
             coherences could apparently be observed in water and other
             concentrated samples, in direct violation of established
             theory. These results were previously explained in a
             dressed-state framework as manifestations of the coupling
             between the spins and the coil (quantized radiation
             damping). Here we provide details of previously communicated
             experimental explorations of these effects [J. Chem. Phys.
             96, 1659 (1992)], and we extend these results to
             multicomponent samples. We observe cross peaks between
             independent molecules in solution in two-dimensional
             experiments, including spectra with multiple-quantum
             coherence transfer echoes; we also demonstrate coherence
             transfer between solvent and (dilute) solute molecules.
             However, we show that these intermolecular cross peaks are
             induced by a mechanism which is local in nature, and thus
             radiation damping (either classical or quantized) cannot
             provide the bulk of the explanation for their occurrence.
             Simulations and analytical results show that the dipolar
             demagnetizing field can account for many of these surprising
             effects, although a complete picture must be more complex.
             © 1993 American Institute of Physics.},
   Key = {fds234390}
}

@article{fds234391,
   Author = {Warren, WS and Rabitz, H and Dahleh, M},
   Title = {Coherent control of quantum dynamics: The dream is
             alive},
   Journal = {Science},
   Volume = {259},
   Number = {5101},
   Pages = {1581-1589},
   Year = {1993},
   Abstract = {Current experimental and theoretical progress toward the
             goal of controlling quantum dynamics is summarized. Two key
             developments have now revitalized the field. First,
             appropriate ultrafast laser pulse shaping capabilities have
             only recently become practical. Second, the introduction of
             engineering control concepts has put the required
             theoretical framework on a rigorous foundation.
             Extrapolations to determine what is realistically possible
             are presented.},
   Key = {fds234391}
}

@article{fds234393,
   Author = {Warren, WS and Richter, W and Andreotti, AH and II,
             BTF},
   Title = {Generation of impossible cross-peaks between bulk water and
             biomolecules in solution NMR},
   Journal = {Science},
   Volume = {262},
   Number = {5142},
   Pages = {2005-2009},
   Year = {1993},
   Abstract = {Intermolecular multiple-quantum coherences between bulk
             water and a glycoprotein fragment at modest concentration
             (20 mM) have been experimentally produced and detected,
             although such coherences are inconceivable in the normal
             theoretical framework of nuclear magnetic resonance. A
             density matrix treatment explains these results by including
             the long-range dipolar interaction between spins and by
             discarding the high-temperature approximation. These results
             imply that peak intensities (critical for structural
             determinations) can be distorted in many gradient
             experiments, and show that magic-angle gradients provide
             substantial improvements with reduced gradient strengths.
             They also suggest methods for contrast enhancement in
             magnetic resonance imaging.},
   Key = {fds234393}
}

@article{fds234379,
   Author = {Warren, WS and He, Q and McCoy, M and Spano, FC},
   Title = {Reply to the comment on: Is multiple quantum nuclear
             magnetic resonance of water real? [5]},
   Journal = {Journal of Chemical Physics},
   Volume = {96},
   Number = {2},
   Pages = {1659-1661},
   Year = {1992},
   ISSN = {0021-9606},
   Key = {fds234379}
}

@article{fds234380,
   Author = {Kuhn, A and Coulston, GW and He, GZ and Schiemann, S and Bergmann, K and Warren, WS},
   Title = {Population transfer by stimulated Raman scattering with
             delayed pulses using spectrally broad light},
   Journal = {Journal of Chemical Physics},
   Volume = {96},
   Number = {6},
   Pages = {4215-4223},
   Year = {1992},
   ISSN = {0021-9606},
   Abstract = {The feasability of selective and complete population
             transfer between atomic or molecular levels by stimulated
             Raman scattering with delayed pulses involving spectrally
             broad light with characteristics typical for pulsed lasers
             is investigated. In extension of previous work, the effect
             on the transfer efficiency of phase fluctuations and of the
             detuning ΔR of the laser frequencies from the two-photon
             resonance is analyzed. The minimum pulse energy Pmin
             required to achieve a transfer efficiency of nearly unity is
             derived analytically, with some restrictions imposed on the
             type of phase fluctuations. Pmin increases approximately
             proportional to the square of the bandwidth of the laser
             radiation and to the square of ΔR. The conclusions are
             confirmed by the results of extensive numerical
             calculations. These studies also reveal a high sensitivity
             of the transfer efficiency to the autocorrelation of the
             fluctuating light. © 1992 American Institute of
             Physics.},
   Key = {fds234380}
}

@article{fds234381,
   Author = {Melinger, JS and Gandhi, SR and Hariharan, A and Tull, JX and Warren,
             WS},
   Title = {Generation of narrowband inversion with broadband laser
             pulses},
   Journal = {Physical Review Letters},
   Volume = {68},
   Number = {13},
   Pages = {2000-2003},
   Year = {1992},
   ISSN = {0031-9007},
   url = {http://dx.doi.org/10.1103/PhysRevLett.68.2000},
   Abstract = {We show experimentally, here for Na vapor, and theoretically
             that picosecond frequency-swept laser pulses create in
             multilevel systems an inversion profile that is far narrower
             than the pulse spectrum. This selectivity persists even when
             the Rabi frequency is substantially larger than the spacing
             between pumped and suppressed transitions. © 1992 The
             American Physical Society.},
   Doi = {10.1103/PhysRevLett.68.2000},
   Key = {fds234381}
}

@article{fds234382,
   Author = {McDonald, SD and Warren, WS},
   Title = {Testing the limits of shape optimization by large-flip-angle
             pulses},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {99},
   Number = {2},
   Pages = {282-291},
   Year = {1992},
   ISSN = {0022-2364},
   Abstract = {Optimized waveforms for inverting pulses with areas up to
             9π are reported. Both differences and similarities in
             rectangularity of inversion and sensitivity to inhomogeneity
             are found. For some applications many-π pulses may be more
             useful than low-flip-angle pulses. © 1992.},
   Key = {fds234382}
}

@article{fds234383,
   Author = {McCoy, MA and Warren, WS},
   Title = {Pulse shaping in quadrupole-echo NMR},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {98},
   Number = {1},
   Pages = {24-35},
   Year = {1992},
   ISSN = {0022-2364},
   Abstract = {Shaped radiofrequency pulses are designed to extend the
             quadrupole-echo excitation bandwidth without insidious phase
             distortions. The quadrupole-shaped pulse (QUASH) is
             constructed by a simple iterative optimization procedure
             which directly solves a density-matrix equation of motion
             for an arbitrary amplitude-modulated pulse acting on a
             three-level system. Computer simulations and experimental 2H
             NMR studies comparing the performance of simple rectangular,
             composite, and shaped quadrupole-echo sequences on the
             partially rotating methyl group on 1-alanine-d3,3,3 show a
             dramatic improvement using the shaped excitation pulse.
             Increases in the effective bandwidth by a factor of two and
             three were realized over composite and rectangular
             sequences, respectively, without phase distortions. ©
             1992.},
   Key = {fds234383}
}

@article{fds234384,
   Author = {Warren, WS and Mayr, S and Goswami, D and Jr, APW},
   Title = {Laser-enhanced NMR spectroscopy},
   Journal = {Science},
   Volume = {255},
   Number = {5052},
   Pages = {1683-1685},
   Year = {1992},
   ISSN = {0036-8075},
   Abstract = {Experimental studies show that optical irradation far from
             any absorption bands can shift the resonances in a nuclear
             magnetic resonance (NMR) spectrum without significant
             heating. This effect may lead to increased dispersion in NMR
             studies of complex molecules.},
   Key = {fds234384}
}

@article{fds234378,
   Author = {Melinger, JS and Hariharan, A and Gandhi, SR and Warren,
             WS},
   Title = {Adiabatic population inversion in I2 vapor with
             picosecond laser pulses},
   Journal = {Journal of Chemical Physics},
   Volume = {95},
   Number = {3},
   Pages = {2210-2213},
   Year = {1991},
   ISSN = {0021-9606},
   Key = {fds234378}
}

@article{fds234374,
   Author = {Spano, FC and Warren, WS},
   Title = {Photon echo decays in optically dense media},
   Journal = {Journal of Chemical Physics},
   Volume = {93},
   Number = {3},
   Pages = {1546-1556},
   Year = {1990},
   ISSN = {0021-9606},
   Abstract = {In this paper we investigate the influence of optical
             density or superradiance on the photon echo decay using the
             coupled Maxwell-Bloch equations. Our theory applies to
             optically thick but dilute media, where the transition
             dipole-dipole interaction between nearby chromophores is
             negligible, but the far-field interaction is not.
             Corrections to the (normalized) echo decay in the optically
             thin limit, IeN(tπ) = exp [-4tπ/T2] (tπ and T2 are the
             interpulse separation times and the coherence relaxation
             times, respectively), are found by expanding the
             polarization, excited state population and pulse electric
             fields in powers of ζ = αz, where α is the inverse Beer's
             absorption length, and z is the coordinate along the pulse
             propagation axis. Numerical solutions for optically thick
             samples are also presented, and when ζ≫ 1 the normalized
             echo intensity is found to obey the simple analytic form:
             IeN(tπ) = 2 exp [- t π/T1] - 1, when tπ/T1&lt;1n 2 and
             IeN (tπ) = 0 for longer times. (T 1 is the population
             relaxation time.) In this limit the echo decay is
             independent of the coherence relaxation time T2,
             illustrating the profound effect intermolecular coupling may
             have on any nonlinear optical measurement. We show that at
             low temperatures, when T2 = 2T 1, the echo decay rate
             increases as the optical density increases. However, for
             higher temperatures, when T2 is sufficiently shorter than
             2T1, the opposite behavior results, that is, the echo decay
             rate decreases as the optical density increases. © 1990
             American Institute of Physics.},
   Key = {fds234374}
}

@article{fds234375,
   Author = {Haner, M and Warren, WS},
   Title = {Investigation of momentum relaxation and time-dependent
             conductance in radiation-damaged GaAs},
   Journal = {Physical Review B - Condensed Matter and Materials
             Physics},
   Volume = {41},
   Number = {9},
   Pages = {5792-5798},
   Year = {1990},
   ISSN = {0163-1829},
   url = {http://dx.doi.org/10.1103/PhysRevB.41.5792},
   Abstract = {We report experimental characterization of a transient
             capacitative electrical effect in a GaAs photoconductive
             switch due to initial momentum relaxation of the carriers
             within the photoexcited plasma. The carrier-momentum-dampening
             rate (d) of approximately 1 ps is characterized by optical
             square-pulse excitation in a radiation-damaged GaAs
             substrate, which produces asymmetries in the electrical
             impulse response of the photoconductor. Defect densities in
             the radiation-damaged samples are measured with use of
             medium-energy Rutherford backscattering and correlated with
             the electrical characteristics. Simulations of the electron
             transport and electrical response under our experimental
             conditions agree favorably with the observed electrical
             characteristics of the photoconductor. We discuss the effect
             of plasma dampening on electrical-switching characteristics
             and the site-defect capture process. © 1990 The American
             Physical Society.},
   Doi = {10.1103/PhysRevB.41.5792},
   Key = {fds234375}
}

@article{fds234376,
   Author = {McCoy, MA and Warren, WS},
   Title = {Three-quantum nuclear magnetic resonance spectroscopy of
             liquid water: Intermolecular multiple-quantum coherence
             generated by spin-cavity coupling},
   Journal = {Journal of Chemical Physics},
   Volume = {93},
   Number = {1},
   Pages = {858-860},
   Year = {1990},
   ISSN = {0021-9606},
   Key = {fds234376}
}

@article{fds234377,
   Author = {Judson, RS and Lehmann, KK and Rabitz, H and Warren,
             WS},
   Title = {Optimal design of external fields for controlling molecular
             motion: application to rotation},
   Journal = {Journal of Molecular Structure},
   Volume = {223},
   Number = {C},
   Pages = {425-456},
   Year = {1990},
   ISSN = {0022-2860},
   url = {http://dx.doi.org/10.1016/0022-2860(90)80485-3},
   Abstract = {A general discussion of quantum controllability leads to the
             specific focus of this work, namely the use of tailored
             radiation to excite rotational states, either specific
             |JM〉 states or superposition states which correspond to a
             high degree of molecular orientation. It is shown that
             starting from the |00&gt; state it is in principle possible
             to produce any eigenstate or superposition state given a
             long enough pulse and specific examples are presented.
             Highly ordered states, which are useful in a variety of
             spectroscopic applications, can be prepared by realistic
             tailored microwave fields. © 1990.},
   Doi = {10.1016/0022-2860(90)80485-3},
   Key = {fds234377}
}

@article{fds234369,
   Author = {Warren, WS and Hammes, SL and Bates, JL},
   Title = {Dynamics of radiation damping in nuclear magnetic
             resonance},
   Journal = {Journal of Chemical Physics},
   Volume = {91},
   Number = {10},
   Pages = {5895-5904},
   Year = {1989},
   ISSN = {0021-9606},
   Abstract = {The time evolution of spins-1/2 subject to radiation
             damping, which is commonly encountered for solvent peaks at
             high field, is examined in detail. The well-known analytic
             results for rectangular pulses on undamped spin-1/2 systems
             are extended to the radiation damped case, and reveal
             surprisingly complex dynamics. Explanations in terms of
             Bloch vectors are also presented, and composite pulse
             sequences which would also be insensitive to radiation
             damping are proposed. In addition, gradient optimization
             programs were developed to find shaped π and π/2 pulses
             insensitive to radiation damping. The optimized pulses
             compensate for radiation damping effects even when the
             characteristic damping time is shorter than the pulse
             length. © 1989 American Institute of Physics.},
   Key = {fds234369}
}

@article{fds234370,
   Author = {Warren, WS},
   Title = {Spectroscopic applications of programmable subpicosecond
             resolution laser pulse shaping},
   Journal = {CONFERENCE ON LASERS AND ELECTRO-0PTICS},
   Pages = {154-},
   Year = {1989},
   Abstract = {A method has been developed for producing
             voltage-programmable, arbitrarily shaped laser pulses with
             ~100-fs resolution and &gt;107-W peak power. Rectangular
             600-1500-fs pulses have been used to probe hot carrier
             relaxation by photoconductive sampling, and phase- and
             amplitude-modulated laser pulses have been used to create
             complex solitons in optical fibers. Other applications that
             illustrate the use of shaped laser pulses in atomic and
             molecular spectroscopy are briefly described, as is the use
             of optical analogs of spin-locking experiments to turn off
             intramolecular vibrational redistribution.},
   Key = {fds234370}
}

@article{fds234371,
   Author = {Spano, FC and Warren, WS},
   Title = {Understanding dephasing in mixed molecular crystals. II.
             Semiclassical dephasing and superradiance for hundreds of
             coupled absorbers},
   Journal = {Journal of Chemical Physics},
   Volume = {90},
   Number = {11},
   Pages = {6034-6046},
   Year = {1989},
   ISSN = {0021-9606},
   Abstract = {We numerically investigate optical dephasing from as many as
             500 interacting two-level absorbers by making the
             semiclassical approximation on the radiation-matter
             interaction which includes retarded dipole-dipole coupling
             and superradiant coupling. We calculate the superradiant
             decay rate following single pulse optical excitation, the
             photon echo decay and the fluorescence. By carrying out an
             expansion to the second order in time we demonstrate a
             fundamental difference between the homogeneous
             free-induction decay and photon echo decay which is due to
             radiation damping. We show that an echo sequence is capable
             of reversing superradiant damping in some cases. Specific
             computations for pentacene doped mixed molecular crystals,
             where "domains" of resonant impurities are likely to exist,
             are presented and compared with experimental results. ©
             1989 American Institute of Physics.},
   Key = {fds234371}
}

@article{fds234372,
   Author = {Lee, CJ and Warren, WS},
   Title = {Symmetry properties of coupled spin systems under
             arbitrarily shaped radiofrequency pulse fields},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {82},
   Number = {1},
   Pages = {185-192},
   Year = {1989},
   ISSN = {0022-2364},
   url = {http://dx.doi.org/10.1016/0022-2364(89)90181-9},
   Doi = {10.1016/0022-2364(89)90181-9},
   Key = {fds234372}
}

@article{fds234373,
   Author = {Lee, CJ and Murali, N and Warren, WS},
   Title = {NMR dipole-dipole refocusing with shaped
             pulses},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {84},
   Number = {3},
   Pages = {643-647},
   Year = {1989},
   ISSN = {0022-2364},
   Key = {fds234373}
}

@article{fds234569,
   Author = {Wooldridge, PJ and Bates, JL and Lin, CP and Warren,
             WS},
   Title = {Energy redistribution from high vibrational levels populated
             by stimulated emission pumping},
   Pages = {44-},
   Year = {1989},
   Abstract = {Laser pulses with finely controlled amplitude envelopes can
             selectively invert a portion of a Doppler broadened line,
             but the extent of inversion varies as the Rabi frequency of
             the transition changes. Modulation of the phase in addition
             to the amplitude can compensate for Rabi frequency
             variations, and pulses can be designed to invert a
             transition completely over a chosen well-defined frequency
             range. Using such a pulse, ground-state molecules within a
             selected range of velocities can be put into an
             electronically excited state and with a second pulse
             subsequently transferred to a high vibrational level of the
             ground electronic state. Excitation of a narrow and
             well-defined portion of a Doppler profile allows not only
             vibrational and rotational thermalization of the molecules
             to be followed but also subtle changes in translational
             energy of the state. Collisional cross sections of
             ground-state molecules with many vibrational quanta can be
             directly compared with cross sections obtained from
             electronically excited molecules to reveal electronic state
             contributions to collisional dynamics.},
   Key = {fds234569}
}

@article{fds234570,
   Author = {Warren, WS},
   Title = {Spectroscopic applications of programmable subpicosecond
             resolution laser pulse shaping},
   Pages = {82-84},
   Year = {1989},
   Abstract = {A method has been developed for producing
             voltage-programmable, arbitrarily shaped laser pulses with
             approximately 100-fs resolution and &gt;107-W peak power.
             Rectangular 600-1500-fs pulses have been used to probe hot
             carrier relaxation by photoconductive sampling, and phase-
             and amplitude-modulated laser pulses have been used to
             create complex solitons in optical fibers. Other
             applications that illustrate the use of shaped laser pulses
             in atomic and molecular spectroscopy are briefly described,
             as is the use of optical analogs of spin-locking experiments
             to turn off intramolecular vibrational redistribution.},
   Key = {fds234570}
}

@article{fds234559,
   Author = {Spano, FC and Warren, WS},
   Title = {Preparation of constant-bandwidth total inversion,
             independent of optical density, with phase-modulated laser
             pulses},
   Journal = {Physical Review A - Atomic, Molecular, and Optical
             Physics},
   Volume = {37},
   Number = {3},
   Pages = {1013-1016},
   Year = {1988},
   ISSN = {1050-2947},
   url = {http://dx.doi.org/10.1103/PhysRevA.37.1013},
   Abstract = {We show that pulses of electromagnetic radiation with a
             hyperbolic-secant envelope and a hyperbolic-tangent
             frequency sweep are capable of exciting an inversion line
             shape in a collection of two-level absorbers that is highly
             insensitive to optical density. This is not true of the
             hyperbolic-secant pulse (with no frequency modulation) which
             undergoes significant reshaping as it propagates. The
             analysis is based on numerical solutions of the coupled
             Maxwell-Bloch equations in both the plane-wave and paraxial
             approximations. We also show an additional insensitivity of
             the inversion profile to finite relaxation times (T2) that
             approach the pulse width. © 1988 The American Physical
             Society.},
   Doi = {10.1103/PhysRevA.37.1013},
   Key = {fds234559}
}

@article{fds234560,
   Author = {Spano, FC and Warren, WS},
   Title = {Understanding dephasing in mixed molecular crystals. I.
             Photon echoes from dimers revisited},
   Journal = {Journal of Chemical Physics},
   Volume = {89},
   Number = {9},
   Pages = {5492-5497},
   Year = {1988},
   ISSN = {0021-9606},
   Abstract = {We show that a fundamental assumption used in analyzing
             photon echo decays from interacting molecules - the
             assumption that the "pure" dephasing rate can be obtained by
             subtracting one half of the fluorescence decay rate (2T1)-1
             from the photon echo decay rate-is generally inconsistent
             with a fully quantum mechanical treatment. The density
             matrix evolution for a system of noninteracting dimers is
             calculated using the retarded electromagnetic coupling
             between two oscillating dipoles. We are able to properly
             include the effects of spontaneous emission and Dicke
             superradiance on the echo decay. © 1988 American Institute
             of Physics.},
   Key = {fds234560}
}

@article{fds234561,
   Author = {Edelman, RR and Atkinson, DJ and Silver, MS and Loaiza, F and Warren,
             WS},
   Title = {FRODO pulse sequences: A new means of eliminating motion,
             flow and wraparound artifacts},
   Journal = {Radiology},
   Volume = {166},
   Number = {1 I},
   Pages = {231-236},
   Year = {1988},
   Abstract = {Magnetic resonance images of the spine, chest, abdomen, and
             pelvis are commonly degraded by ghost artifacts. The authors
             have developed a new technique named FRODO (Flow and
             Respiratory artifact Obliteration with Directed Orthogonal
             pulses) to suppress these artifacts. Signal from tissues
             responsible for the artifacts is eliminated by use of radio
             frequency pulses specifically optimized for high selectivity
             to saturate proton magnetization over one or more
             independently defined slabs (large rectangular volumes) of
             tissue. Ghost artifacts from pulsatile flow in the heart and
             blood vessels, as well as from respiratory motion and
             swallowing, are suppressed. Additional applications of this
             technique include elimination of intraluminal signal in
             blood vessels and suppression of wraparound artifact along
             the phase-encoding axis. Preliminary clinical experience
             suggests that the FRODO technique, in conjunction with other
             flow compensation methods, may provide a definitive solution
             to the problem of motion in spine imaging. FRODO pulse
             sequences may also prove useful for imaging of blood
             vessels, heart, abdomen, and other areas where motion, flow,
             or wraparound artifacts limit image quality.},
   Key = {fds234561}
}

@article{fds234562,
   Author = {Warren, WS},
   Title = {Effects of pulse shaping in laser spectroscopy and nuclear
             magnetic resonance.},
   Journal = {Science},
   Volume = {242},
   Number = {4880},
   Pages = {878-884},
   Year = {1988},
   Abstract = {Pulsed excitation fields are routinely used in most laser
             and nuclear magnetic resonance (NMR) experiments. In the NMR
             case, constant amplitude (rectangular) pulses have
             traditionally been used; in laser spectroscopy the exact
             pulse shape is often unknown or changes from shot to shot.
             This article is an overview of the effects of
             radio-frequency and laser pulse shapes and the instrumental
             requirements for pulse shaping. NMR applications to
             selective excitation, solvent suppression, elimination of
             phase roll, and reduced power dissipation are discussed, as
             are optical applications to soliton generation, velocity
             selective excitation, and quantitative population
             transfer.},
   Key = {fds234562}
}

@article{fds234563,
   Author = {Mahajan, AB and Warren, WS and Paszek, MJ and Olarte, F and Jr,
             AC},
   Title = {Neonatal Campylobacter meningitis.},
   Journal = {Pennsylvania Medicine},
   Volume = {91},
   Number = {1},
   Pages = {58-61},
   Year = {1988},
   Key = {fds234563}
}

@article{fds234564,
   Author = {Hasenfeld, A and Hammes, SL and Warren, WS},
   Title = {Understanding of phase modulation in two-level systems
             through inverse scattering},
   Journal = {Physical Review A - Atomic, Molecular, and Optical
             Physics},
   Volume = {38},
   Number = {5},
   Pages = {2678-2681},
   Year = {1988},
   ISSN = {1050-2947},
   url = {http://dx.doi.org/10.1103/PhysRevA.38.2678},
   Abstract = {Analytical and numerical calculations describe the effects
             of shaped radiation pulses on two-level systems in terms of
             quantum-mechanical scattering. Previous results obtained in
             the reduced case of amplitude modulation are extended to the
             general case of simultaneous amplitude and phase modulation.
             We show that an infinite family of phase- and
             amplitude-modulated pulses all generate rectangular
             inversion profiles. Experimental measurements also verify
             the theoretical analysis. © 1988 The American Physical
             Society.},
   Doi = {10.1103/PhysRevA.38.2678},
   Key = {fds234564}
}

@article{fds234565,
   Author = {Loaiza, F and McCoy, MA and Levitt, MH and Silver, MS and Warren,
             WS},
   Title = {Excitation performance in inhomogeneously broadened
             systems},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {76},
   Number = {3},
   Pages = {504-527},
   Year = {1988},
   ISSN = {0022-2364},
   Abstract = {The problem of predicting through numerical simulation the
             performance of pulse sequences applied to inhomogeneously
             broadened spin systems is examined. Numerical or analytical
             calculations of the dependence of magnetization on frequency
             do not lead immediately to the actual form of the spectrum
             in the inhomogeneously broadened case. To predict the
             spectrum it is usually necessary to proceed through the time
             domain and to take into account the fact that the
             experimental data of negative times are usually not
             accessible. These results are particularly relevant to the
             optimization of pulse sequences for multislice imaging at
             zero gap. Experimental results from high-resolution NMR and
             magnetic resonance imaging verify these ideas. ©
             1988.},
   Key = {fds234565}
}

@article{fds234566,
   Author = {Haner, M and Warren, WS},
   Title = {Synthesis of crafted optical pulses by time domain
             modulation in a fiber-grating compressor},
   Journal = {Applied Physics Letters},
   Volume = {52},
   Number = {18},
   Pages = {1458-1460},
   Year = {1988},
   ISSN = {0003-6951},
   url = {http://dx.doi.org/10.1063/1.99097},
   Abstract = {We report a method for direct generation of voltage
             programmable, arbitrarily shaped laser pulses of
             subpicosecond duration and roughly 100 fs resolution. A
             waveguide intensity modulator was fabricated and
             incorporated into a fiber-grating pulse compressor to shape
             temporally the chirped pulse before compression. Optical
             pulses with sin(x)/x and square envelopes are synthesized to
             demonstrate the technique.},
   Doi = {10.1063/1.99097},
   Key = {fds234566}
}

@article{fds234567,
   Author = {McCoy, MA and Loaiza, F and Valentine, K and Warren,
             WS},
   Title = {Self-refocused solvent suppression with shaped
             pulses},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {80},
   Number = {1},
   Pages = {155-161},
   Year = {1988},
   ISSN = {0022-2364},
   Key = {fds234567}
}

@article{fds234568,
   Author = {Loaiza, F and McCoy, MA and Hammes, SL and Warren,
             WS},
   Title = {Selective excitation without phase distortion using
             self-refocused amplitude- and amplitude/phase-modulated
             pulses},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {77},
   Number = {1},
   Pages = {175-181},
   Year = {1988},
   ISSN = {0022-2364},
   Key = {fds234568}
}

@article{fds234552,
   Author = {Lin, CP and Bates, J and Mayer, JT and Warren, WS},
   Title = {Implementation of a phase and amplitude modulated π pulse
             for coherent optical spectroscopy},
   Journal = {Journal of Chemical Physics},
   Volume = {86},
   Number = {6},
   Pages = {3750-3751},
   Year = {1987},
   ISSN = {0021-9606},
   Key = {fds234552}
}

@article{fds234553,
   Author = {Warren, WS},
   Title = {EFFECTS OF PULSE SHAPING IN LASER SPECTROSCOPY.},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {742},
   Pages = {42-46},
   Year = {1987},
   Abstract = {We have shown theoretically and experimentally that
             specially shaped laser pulses can give enhanced excitation
             selectivity, compensate for experimental complications such
             as inhomogeneities and pulse amplitude jitter, and cleanly
             pump forbidden transitions. A new approach to generating
             picosecond pulses, which does not require modelocking,
             permits software controlled, arbitrarily shaped (phase and
             amplitude modulated) pulses with roughly 1 ps
             resolution.},
   Key = {fds234553}
}

@article{fds234554,
   Author = {Warren, WS and Pickering, M},
   Title = {Student strategies in a junior-level procedureless
             laboratory},
   Journal = {Journal of Chemical Education},
   Volume = {64},
   Number = {1},
   Pages = {68-69},
   Year = {1987},
   ISSN = {0021-9584},
   Key = {fds234554}
}

@article{fds234555,
   Author = {Loaiza, F and McCoy, MA and Warren, WS and Silver, MS and Egloff,
             H},
   Title = {Crafted pulses for imaging and in vivo NMR
             spectroscopy},
   Journal = {Annals of the New York Academy of Sciences},
   Volume = {508},
   Pages = {483-487},
   Year = {1987},
   Key = {fds234555}
}

@article{fds234556,
   Author = {McCoy, M and Warren, WS},
   Title = {Pulse shaping to improve performance of NMR multiple-pulse
             sequences: 2-D solvent-suppressed cosy of vitamin
             B1 in water},
   Journal = {Chemical Physics Letters},
   Volume = {133},
   Number = {2},
   Pages = {165-170},
   Year = {1987},
   ISSN = {0009-2614},
   url = {http://dx.doi.org/10.1016/0009-2614(87)87043-4},
   Abstract = {Grafted "narrow reject" pulse shapes, whicch were shown
             previously to be capable of uniformly exciting a wide range
             of resonance frequencies with a sharp null directly on
             resonance for solvent suppression, are combined to generate
             multiple-pulse sequences. In particular, we show that
             two-dimensional solvent-suppressed spectra can be obtained
             with such pulses. This is the first application of pulse
             Grafting to high-resolution, multiple-pulse NMR
             spectroscopy. © 1987.},
   Doi = {10.1016/0009-2614(87)87043-4},
   Key = {fds234556}
}

@article{fds234557,
   Author = {Lin, CP and Bates, J and Mayer, JT and Warren, WS},
   Title = {Erratum: Implementation of a phase and amplitude modulated
             π pulse for coherent optical spectroscopy (Journal of
             Chemical Physics (1987) 86 (3750))},
   Journal = {Journal of Chemical Physics},
   Volume = {87},
   Number = {7},
   Pages = {4241-},
   Year = {1987},
   ISSN = {0021-9606},
   Key = {fds234557}
}

@article{fds234558,
   Author = {Spzno, F and Haner, M and Warren, WS},
   Title = {Spectroscopic demonstration of picosecond, phase-shifted
             laser multiple-pulse sequences},
   Journal = {Chemical Physics Letters},
   Volume = {135},
   Number = {1-2},
   Pages = {97-102},
   Year = {1987},
   ISSN = {0009-2614},
   url = {http://dx.doi.org/10.1016/0009-2614(87)87224-X},
   Abstract = {We show that the concept of phase-shifted laser pulse trains
             is meaningful only for purely amplitude-modulated pulses,
             and probably cannot be generalized to use the output of a
             normal pulsed laser. We demonstrate a laser system which
             gives picosecond pulse lengths, picosecond or nanosecond
             interpulse delays, and complete phase control. This makes
             most molecular transitions amenable to the coherent
             techniques previously restricted to nuclear magnetic
             resonance. Fluorescence suppression by π phase shifts is
             demonstrated for the first time with picosecond pulses and
             long delays. © 1987.},
   Doi = {10.1016/0009-2614(87)87224-X},
   Key = {fds234558}
}

@article{fds234550,
   Author = {Spano, F and Warren, WS},
   Title = {THEORETICAL ANALYSIS OF INJECTION-LOCKED DYE LASERS: AN
             APPLICATION TO THE GENERATION OF OPTICAL PULSE SEQUENCES
             WITH PHASE CONTROL.},
   Journal = {Proceedings of SPIE - The International Society for Optical
             Engineering},
   Volume = {620},
   Pages = {52-56},
   Year = {1986},
   Abstract = {A theoretical model based on the laser rate equations is
             used to describe injection locking in pulsed dye lasers. It
             is shown that, in general, the frequency of the injection
             locked pulse is not equal to the frequency of the cw
             light-an unexpected result since the two are related through
             stimulated emission. We discuss how to accommodate this
             feature in the design of a specialized delay line used to
             create optical pulse sequences with variable phase shifts
             between the pulses.},
   Key = {fds234550}
}

@article{fds234551,
   Author = {Loaiza, F and Lim, K-T and Warren, WS},
   Title = {Crafted pulses and pulse sequences for MR
             imaging},
   Journal = {Health Care Instrumentation},
   Volume = {1},
   Number = {6},
   Pages = {188-194},
   Year = {1986},
   Key = {fds234551}
}

@article{fds234547,
   Author = {Gutow, JH and McCoy, M and Spano, F and Warren, WS},
   Title = {Crafted pulses for the uniform suppression of a region in a
             coherent spectrum},
   Journal = {Physical Review Letters},
   Volume = {55},
   Number = {10},
   Pages = {1090-1093},
   Year = {1985},
   ISSN = {0031-9007},
   url = {http://dx.doi.org/10.1103/PhysRevLett.55.1090},
   Abstract = {We have theoretically derived and experimentally
             demonstrated "narrow reject" pulses which give a uniform 2
             excitation off resonance, and zero excitation in a sharp
             hole directly on resonance. They are also insensitive to
             relaxation effects. This shape is symmetric and has only
             amplitude modulation, and so it can be implemented on most
             commercial NMR spectrometers or with laser modulators. It
             can replace conventional broadband 2 pulses in most NMR or
             laser pulse sequences, in order to give solvent suppression
             or measure spectral diffusion. © 1985 The American Physical
             Society.},
   Doi = {10.1103/PhysRevLett.55.1090},
   Key = {fds234547}
}

@article{fds234548,
   Author = {Banash, MA and Warren, WS},
   Title = {COHERENT AND INCOHERENT DUAL-FREQUENCY OPTICAL SPECTROSCOPY:
             APPLICATIONS TO GAS PHASE COLLISIONAL DYNAMICS.},
   Pages = {132-133},
   Year = {1985},
   Abstract = {Summary form only given. The authors present work with
             coherent and incoherent dual-frequency experiments designed
             to measure detailed microscopic collisional dynamics in
             molecular gases. In the incoherent version, a laser pulse
             sequence consisting of two 180 degree pulses (each 100 ns
             long) is applied. Each pulse has a bandwidth such that only
             a narrow range of velocities in the Doppler profile is
             excited. As both pulses are 180 degree and not phase
             specific, this incoherent experiment measures population
             transfer between velocity ranges. In the coherent version
             both pulses are 90 degree and phase specific, so the
             experiment measures collisional effects on phase
             memory.},
   Key = {fds234548}
}

@article{fds234549,
   Author = {McCoy, MA and Warren, WS},
   Title = {Implementation of simple crafted 90 or 180° pulse shapes in
             fourier transform NMR spectroscopy},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {65},
   Number = {1},
   Pages = {178-182},
   Year = {1985},
   ISSN = {0022-2364},
   Key = {fds234549}
}

@article{fds234542,
   Author = {Warren, WS},
   Title = {Effects of arbitrary laser or NMR pulse shapes on population
             inversion and coherence},
   Journal = {Journal of Chemical Physics},
   Volume = {81},
   Number = {12},
   Pages = {5437-5448},
   Year = {1984},
   ISSN = {0021-9606},
   Abstract = {We present a new perturbation expansion for calculating the
             effects of arbitrary pulse shapes in two-level systems, even
             when the effects are grossly nonlinear. The first two terms
             have simple physical interpretations. This expansion
             converges rapidly for all values of resonance offset with
             simple shapes, and for any pulse shape far from resonance.
             We generate very simple, symmetric, single phase pulse
             shapes which produce uniform inversion or polarization and
             which can be combined into multiple pulse sequences. We also
             show that pulse shape modification is superior to
             construction of composite pulse sequences, since such
             sequences must become erratic far from resonance. © 1984
             American Institute of Physics.},
   Key = {fds234542}
}

@article{fds234543,
   Author = {Banash, M and Loiza, F and Spano, F and Warren, WS},
   Title = {PHASE COHERENT LASER MUTIPLE-PULSE SPECTROSCOPY.},
   Pages = {131-},
   Year = {1984},
   Key = {fds234543}
}

@article{fds234544,
   Author = {Warren, WS and Murdoch, JB and Pines, A},
   Title = {Computer simulations of multiple-quantum NMR experiments.
             II. Selective excitation},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {60},
   Number = {2},
   Pages = {236-256},
   Year = {1984},
   ISSN = {0022-2364},
   Abstract = {The effects of selective multiple-quantum pulse sequences
             have previously been analyzed by coherent averaging theory.
             However, convergence of the Magnus expansion used for those
             calculations is questionable in the experimentally important
             region of long cycle times. Exact density matrix evolutions
             are calculated here to show when the coherent averaging
             calculations will be reliable. In addition, simple selective
             sequences which cannot be treated by coherent averaging
             theory are also analyzed. © 1984.},
   Key = {fds234544}
}

@article{fds234545,
   Author = {Murdoch, JB and Warren, WS and Weitekamp, DP and Pines,
             A},
   Title = {Computer simulations of multiple-quantum NMR experiments. I.
             Nonselective excitation},
   Journal = {Journal of Magnetic Resonance (1969)},
   Volume = {60},
   Number = {2},
   Pages = {205-235},
   Year = {1984},
   ISSN = {0022-2364},
   Abstract = {The multiple-quantum (MQ evolution of anisotropic spin
             systems with four to eight coupled protons is analyzed using
             a computer for the basic three-pulse sequence. MQ
             intensities are first investigated as a function of
             preparation time. The concept of time-independent
             intensities is then introduced, and an algorithm for
             efficient computation of these quantities is described. A
             correlation between the distribution of dipolar coupling
             values and the intensity of high-quantum lines is discussed;
             in many cases, these intensities are predicted to be
             considerably larger than a simple statistical argument would
             suggest. The effect of varying the preparation and detection
             times independently is analyzed as a random walk problem. ©
             1984.},
   Key = {fds234545}
}

@article{fds234546,
   Author = {Banash, MA and Gutow, J and Warren, WS},
   Title = {Luminescence as a probe of coherence: Applications to
             collisional dynamics and phase coherent spectroscopy},
   Journal = {Journal of Luminescence},
   Volume = {31-32},
   Number = {PART 2},
   Pages = {855-857},
   Year = {1984},
   ISSN = {0022-2313},
   Abstract = {Measurement of luminescence rather than polarization in
             coherent optical experiments allows more molecular
             information to be extracted. In this paper we discuss the
             advantages of this technique, such as frequency selectivity
             and time resolution, and applications to gas phase
             collisional dynamics. © 1984.},
   Key = {fds234546}
}

@article{fds234538,
   Author = {Warren, WS and Zewail, AH},
   Title = {Multiple phase-coherent laser pulses in optical
             spectroscopy. I. The technique and experimental
             applications},
   Journal = {Journal of Chemical Physics},
   Volume = {78},
   Number = {5},
   Pages = {2279-2297},
   Year = {1983},
   ISSN = {0021-9606},
   Abstract = {In this series of papers we report on the generation and
             application of multiple pulse phase coherent sequences in
             optical spectroscopy. In this paper the effects of intense
             pulse trains on systems with only two resonant energy levels
             are analyzed, with particular attention to the effects of
             extreme inhomogeneous broadening and population depletion to
             nonresonant levels. It is shown that these effects, which
             are present in virtually all optical systems, make the
             simple gyroscopic model of optical coherent transients
             invalid. Exact calculations show, e.g., that a two-pulse
             photon echo is not maximized by a 1:2 length ratio for the
             pulses; that the maximum excited state population is not
             created by a 180° pulse; and that three equal pulses are
             almost as effective as a 1:2:1 ratio for producing three
             pulse echoes. The role of pulse phase is extensively
             analyzed. Pulse sequences are proposed and experimentally
             demonstrated which permit optical phase sensitive detection
             and measurement of ground state relaxation parameters. The
             experimental results are based on an extension of the
             acousto-optic modulation and fluoresence detection
             techniques of Zewail and Orlowski [Zewail et al., Chem.
             Phys. Lett. 48, 256 (1977); Orlowski et al., ibid 54, 197
             (1978)]. The relative merits of fluorescence and transverse
             polarization detection are discussed, and fluorescence
             detection is shown to be more generally useful for these new
             sequences. Finally, composite pulse trains are shown to be
             capable of substantially increasing the signal available
             from highly inhomogenously broadened transitions. In paper
             II we extend the treatment to multilevel systems with some
             emphasis on solid state applications. © 1983 American
             Institute of Physics.},
   Key = {fds234538}
}

@article{fds234539,
   Author = {Warren, WS and Zewail, AH},
   Title = {Multiple phase-coherent laser pulses in optical
             spectroscopy. II. Applications to multilevel
             systems},
   Journal = {Journal of Chemical Physics},
   Volume = {78},
   Number = {5},
   Pages = {2298-2311},
   Year = {1983},
   ISSN = {0021-9606},
   Abstract = {The effects of intense laser pulse trains in coupled
             multilevel systems (such as pure or mixed molecular
             crystals) are analyzed by calculating exact density matrix
             evolutions. It is shown that two-level approximations are
             inadequate. The contributions of exchange couplings,
             inhomogeneous broadening, permanent multipole interactions
             and transition multipole interactions to absorption and
             photon echo line shapes are calculated. The absorption line
             shape of 1,4-dibromonaphthalene (DBN) is shown to be
             predominantly an isotopic substitution effect, as our Monte
             Carlo results give quantitative agreement with experiment
             for this model. Average t-matrix approximations to the
             Green's function, which have been used to propose a
             different mechanism for the DBN line shape are shown to be
             qualitatively inadequate. Dipole-dipole interactions are
             shown to be an important photon echo decay mechanism in
             mixed crystals, with the relative importance of permanent
             and transition multipole interactions dependent on the
             resonance frequency distribution. Multiple pulse trains,
             including multiple pulse echoes and optical multiple-quantum
             sequences, are shown to be capable of distinguishing
             different types of interactions in the molecular Hamiltonian
             and reducing optical density effects. Specific pulse
             sequences are proposed and their effects are calculated. ©
             1983 American Institute of Physics.},
   Key = {fds234539}
}

@article{fds234540,
   Author = {Warren, WS and Zewail, AH},
   Title = {Optical multiple pulse sequences for multiphoton selective
             excitation and enhancement of forbidden transitions},
   Journal = {Journal of Chemical Physics},
   Volume = {78},
   Number = {6},
   Pages = {3583-3592},
   Year = {1983},
   ISSN = {0021-9606},
   Abstract = {In this paper we present novel and simple pulse sequences
             for enhancing the intensity of forbidden or highly
             nonresonant optical transitions. These sequences provide a
             straightforward approach to circumventing the most serious
             limitation of optical coherent transient spectroscopy:
             Available laser intensities are often insufficient to excite
             a significant fraction of the ground state population into
             desired excited states, either because of large
             inhomogeneous broadening or, in the case of multiphoton
             absorption, large anharmonicities. Optical phase modulation
             (which can be produced by an acousto-optic modulator) or
             amplitude modulation (which can be produced by an
             interferometer) with carefully chosen pulse flip angles and
             delays can effectively remove even very large energy
             mismatches, thus permitting essentially complete population
             inversions arbitrarily far from resonance. Coherent
             averaging theory and computer calculations are used to
             derive particularly valuable sequences. Pumping enhancement
             of 103-10 5 (depending on individual molecular parameters)
             for these modulated pulse sequences are predicted. Specific
             applications to multiphoton pumping of local vibrational
             modes are discussed. © 1983 American institute of
             Physics.},
   Key = {fds234540}
}

@article{fds234541,
   Author = {Jr, WW and Schönherr, G and Hensel, F},
   Title = {Intervalence excitations of a mixed-valence salt: NMR and
             optical absorption in molten InCl2},
   Journal = {Chemical Physics Letters},
   Volume = {96},
   Number = {4},
   Pages = {505-508},
   Year = {1983},
   ISSN = {0009-2614},
   Abstract = {We report115 In nuclear relaxation rates for molten InCl2
             and visible-near-infrared absorption spectra for molten
             InCl2 and In2Cl3. A weak band at 2.1 eV in InCl2 is
             attributed to the intervalence transfer excitation In+ →-
             In3+. The intensity of the intervalence band is correlated
             with the lifetime of the excited, magnetic ion In2+ measured
             by NMR. © 1983.},
   Key = {fds234541}
}

@article{fds234536,
   Author = {Zewall, A and Lambert, W and Felker, P and Perry, J and Warren,
             W},
   Title = {Laser probing of vibrational energy redistribution and
             dephasing},
   Journal = {Journal of Physical Chemistry},
   Volume = {86},
   Number = {7},
   Pages = {1184-1192},
   Year = {1982},
   ISSN = {0022-3654},
   Abstract = {This paper addresses questions important to the origin of
             optical dephasing and vibrational energy redistributions in
             molecules. Several laser techniques are discussed and three
             major findings are presented. These findings are related to
             (a) optical dephasing of molecules in the gas phase and in
             beams, (b) dephasing of high-energy vibrational overtone
             states of large molecules, and (c) energy randomization and
             quantum beats in large molecules (anthracene) excited by
             picosecond pulses and cooled by supersonic jet expansion. ©
             1982 American Chemical Society.},
   Key = {fds234536}
}

@article{fds234537,
   Author = {Warren, WS and Pines, A},
   Title = {Simple pulse sequences for selective multiple-quantum
             excitation},
   Journal = {Chemical Physics Letters},
   Volume = {88},
   Number = {4},
   Pages = {441-443},
   Year = {1982},
   ISSN = {0009-2614},
   Abstract = {A sixteen pulse sequence which excites only four-quantum
             transitions in multiple-quantum NMR is shown to give good
             selectivity on two molecules, benzene and n-butyl bromide.
             The behavior as pulse sequence parameters are varied is
             shown to be consistent with coherent averaging theory.
             Advantages of this new sequence include much lower duty
             cycles and shorter total duration than can be achieved with
             previously used selective sequences. Limitations of this
             approach and extensions to high-quantum selectivity are
             discussed. © 1982.},
   Key = {fds234537}
}

@article{fds234533,
   Author = {Warren, WS and Pines, A},
   Title = {Experiments on selective excitation of multiple-quantum
             transitions in NMR spectroscopy},
   Journal = {Journal of Chemical Physics},
   Volume = {74},
   Number = {5},
   Pages = {2808-2818},
   Year = {1981},
   ISSN = {0021-9606},
   Abstract = {Irradiating a spin system with an appropriate sequence of
             phase shifted pulses excites only certain orders of
             multiple-quantum transitions. Using such sequences in
             preparation and detection produces a large signal/noise
             enhancement for the multiple-quantum spectra over
             nonselective excitation, as predicted from theory. In a
             previous paper the theory was presented in detail. In this
             paper some aspects of the theory are first outlined briefly.
             Experimental results are then presented demonstrating
             four-quantum, six-quantum, and A -symmetry selection in
             oriented benzene and eight-quantum selection in oriented
             1-bromobutane. A six-quantum selective sequence applied to
             benzene with nonequilibrium initial reduced density matrix
             proportional to Ix produces one- and five-quantum spectra.
             The n-quantum signal/noise enhancements are obtained and the
             selectivity is measured as a function of pulse sequence
             parameters. The behavior is that expected if one assumes
             that the limit to selectivity is determined by leading
             nonselective terms in an average Hamiltonian expansion. ©
             1981 American Institute of Physics.},
   Key = {fds234533}
}

@article{fds234534,
   Author = {Warren, WS and Pines, A},
   Title = {Analogy of multiple-quantum NMR to isotopic spin
             labeling},
   Journal = {Journal of the American Chemical Society},
   Volume = {103},
   Number = {7},
   Pages = {1613-1617},
   Year = {1981},
   ISSN = {0002-7863},
   Abstract = {The NMR of oriented molecules gives detailed structural
             information, but isotopic substitution is often required for
             analysis. An alternative to synthesizing labeled molecules
             is to observe multiple-quantum spectra. Symmetry arguments
             show that multiple-quantum transitions yield similar
             information and that the spectra can be predicted by analogy
             with labeling experiments. Several examples are shown to
             illustrate the versatility of this technique for determining
             molecular conformations and rates of intramolecular
             processes. © 1981 American Chemical Society.},
   Key = {fds234534}
}

@article{fds234535,
   Author = {Warren, WS and Zewail, AH},
   Title = {Optical analogs of NMR phase coherent multiple pulse
             spectroscopy},
   Journal = {Journal of Chemical Physics},
   Volume = {75},
   Number = {12},
   Pages = {5956-5958},
   Year = {1981},
   ISSN = {0021-9606},
   Key = {fds234535}
}

@article{fds234368,
   Author = {Warren, WS and Weitekamp, DP and Pines, A},
   Title = {Theory of selective excitation of multiple-quantum
             transitions},
   Journal = {Journal of Chemical Physics},
   Volume = {73},
   Number = {5},
   Pages = {2084-2099},
   Year = {1980},
   ISSN = {0021-9606},
   Abstract = {The question of whether a molecule can be made to absorb and
             emit photons only in groups of n is treated. Pulse sequences
             are introduced which in effect selectively induce the
             absorption of only groups of n photons. This causes only
             n-quantum transitions even when many other transitions might
             be resonant. The technique involves repeated phase shifts of
             2π/n in the radiation to build up the selected coherences
             and cancel all other coherences, and is applicable to a wide
             range of spectroscopic systems. Coherent averaging theory is
             extended to describe selective sequences and demonstrates
             that n-quantum selectivity is possible to arbitrarily high
             order in the average Hamiltonian expansion. High-order
             selectivity requires many phase shifts, however, and for
             this reason the residual nonselective effects of sequences
             which are selective to only a finite order are calculated.
             Selective sequences are applied to the multiple-quantum NMR
             of oriented molecules, where in combination with time
             reversal sequences they produce a much more efficient
             transfer of the population differences into selected
             coherences than is obtainable by normal wideband pumping.
             For example, the 10-quantum transition in a 10-spin system
             can be enhanced by more than four orders of magnitude.
             Experiments on selective excitation of the 4-quantum
             transitions in oriented benzene verify the expected
             enhancement. © 1980 American Institute of
             Physics.},
   Key = {fds234368}
}

@article{fds234367,
   Author = {Warren, WS and Sinton, S and Weitekamp, DP and Pines,
             A},
   Title = {Selective excitation of multiple-quantum coherence in
             nuclear magnetic resonance},
   Journal = {Physical Review Letters},
   Volume = {43},
   Number = {24},
   Pages = {1791-1794},
   Year = {1979},
   ISSN = {0031-9007},
   url = {http://dx.doi.org/10.1103/PhysRevLett.43.1791},
   Abstract = {Wideband selective n-quantum excitation in the NMR of
             coupled spins is demonstrated for the first time. By a
             combination of multiple pulse averaging and phase shifts a
             pure n-quantum excitation operator can be produced (n=2).
             This allows enhancement of normally weak n-quantum
             transitions. Selective excitation of the zero- and
             four-quantum transitions in benzene illustrates this
             approach. Extensions to selective absorption of only groups
             of n photons in other regimes of spectroscopy are
             straight-forward, in principle. © 1979 The American
             Physical Society.},
   Doi = {10.1103/PhysRevLett.43.1791},
   Key = {fds234367}
}

@article{fds234366,
   Author = {Warren, SW},
   Title = {Properties and performance of basic designs of infrared
             interference filters},
   Journal = {Infrared Physics},
   Volume = {8},
   Number = {1},
   Pages = {65-78},
   Year = {1968},
   ISSN = {0020-0891},
   Abstract = {Results of a computer analysis of the basic designs are
             given relating their characteristics with their construction
             and film properties. Data on performance of germanium,
             silicon monoxide filters are given with environmental
             conditions and time. The performance of filters in parallel
             and convergent beams is illustrated. © 1968.},
   Key = {fds234366}
}


%% Chapter in Book   
@misc{fds234506,
   Author = {Warren, WS and Miller, A and Wagner, W and Ye, T and Fischer, M and Yurtsever, G},
   Title = {Two-photon absorption imaging with shaped femtosecond laser
             pulses},
   Journal = {Springer Series in Chemical Physics},
   Volume = {79},
   Series = {Springer Series in Chemical Physics, Vol.
             79},
   Pages = {867-869},
   Booktitle = {Ultrafast Phenomena XIV},
   Publisher = {Springer-Verlag},
   Editor = {Kobayashi, T. and Okada, T. and Kobayashi, T. and Nelson, K.A. and De
             Silvestri, S.},
   Year = {2004},
   ISSN = {0172-6218},
   Abstract = {Femtosecond laser pulse shaping permits background-free
             detection of two-photon absorption, which tends to refill
             spectral holes. This opens up new spectroscopic windows for
             monitoring tissue characteristics.},
   Key = {fds234506}
}

@misc{fds43070,
   Author = {H.S. Tan and E. Schreiber and W.S. Warren},
   Title = {Indirect Pulse Shaping by Parametric Transfer},
   Volume = {XIII},
   Pages = {202-204},
   Booktitle = {Ultrafast Phenomena},
   Publisher = {Springer-Verlag, Berlin},
   Editor = {M.M. Murnane and N.F. Scherer and R.J.D. Miller and A.M.
             Weiner},
   Year = {2002},
   Key = {fds43070}
}

@misc{fds42880,
   Author = {R.R. Rizi and S. Ahn and J. Hopkins and J.S. Leigh and W.S.
             Warren},
   Title = {Contrast Enchancement Based on Intermolecular Zero Quantum
             Coherences for Magnetic Resonance Imaging and
             Microscopy},
   Pages = {53-63},
   Booktitle = {Spatially Resolved Magnetic Resonance},
   Publisher = {VCH Publishing},
   Editor = {P. Blumler and B. Blumich and E. Fukushima},
   Year = {1998},
   Key = {fds42880}
}

@misc{fds43360,
   Author = {R.R. Rizi and S. Ahn and J. Hopkins and J.S. Leigh and W.S.
             Warren},
   Title = {Contrast Enhancement Based on Intermolecular Zero Quantum
             Coherences for Magnetic Resonance Imaging and
             Microscopy},
   Pages = {53-63},
   Booktitle = {Spatially Resolved Magnetic Resonance},
   Publisher = {VCH Publishing},
   Editor = {P. Blumler and B. Blumich and E. Fukushima},
   Year = {1998},
   Key = {fds43360}
}