%% Papers Published @article{fds42878, Author = {D.J. Gauthier and J. Krasinski and R.W. Boyd}, Title = {A novel technique for resonantly enhanced sum-frequency generation involving Rydberg atomic states}, Pages = {517 - 522}, Booktitle = {Coherence and Quantum Optics V}, Publisher = {Plenum, New York}, Editor = {L. Mandel and E. Wolf}, Year = {1983}, Key = {fds42878} } @booklet{Gauthier83, Author = {Gauthier, DJ and Krasinski, J and Boyd, RW}, Title = {Observation of resonantly enhanced sum-frequency generation involving sodium Rydberg states}, Journal = {Optics Letters}, Volume = {8}, Number = {4}, Pages = {211-213}, Publisher = {The Optical Society}, Year = {1983}, Month = {January}, url = {http://dx.doi.org/10.1364/OL.8.000211}, Abstract = {A large, dc-electric-field-induced nonlinear optical susceptibility is exploited to produce ultraviolet radiation in the range 2453-2476 Å by the process of sum-frequency generation in sodium. The interaction is resonantly enhanced at the first intermediate level by the 3 2P3 /2 state and at the second intermediate level by a Rydberg state. Conversion efficiencies of 10-5have been obtained; improvement of this value by a factor of 103should be possible. © 1983 Optical Society of America.}, Doi = {10.1364/OL.8.000211}, Key = {Gauthier83} } @booklet{Boyd84a, Author = {Boyd, RW and Gauthier, DJ and Krasinski, J and Malcuit, MS}, Title = {CONTINUOUSLY TUNABLE SUM-FREQUENCY GENERATION INVOLVING SODIUM RYDBERG STATES.}, Journal = {Ieee Journal of Quantum Electronics}, Volume = {QE-20}, Number = {9}, Pages = {1074-1078}, Publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, Year = {1984}, url = {http://dx.doi.org/10.1109/JQE.1984.1072522}, Abstract = {Broadly tunable sum-frequency generation has been observed in a vapor of atomic sodium in the presence of a dc electric field. This field induces a chi **(**2**) nonlinearity which is resonantly enhanced when the sum frequency corresponds to the energy separation between the ground state and an atomic Rydberg state. In a vapor of number density 4 multiplied by 10**1**4 cm** minus **3, we obtain an energy conversion efficiency as large as 3 multiplied by 10** minus **4 and a chi **(**2**) as large as 1. 2 multiplied by 10** minus **8 ESU. We have also observed sum-frequency generation in the absence of an applied dc field, and we relate these observations to mechanisms that are proposed to explain this effect.}, Doi = {10.1109/JQE.1984.1072522}, Key = {Boyd84a} } @booklet{Boyd84, Author = {R.W. Boyd and D.J. Gauthier and J. Krasinski and M.S. Malcuit}, Title = {Continuously tunable sum-frequency generation involving rydberg states}, Series = {AIP Conference Proceedings}, Number = {119}, Pages = {356 -- 360}, Booktitle = {Laser Techniques in the Extreme Ultraviolet}, Publisher = {American Institute of Physics, New York}, Editor = {S.E. Harris and T.B. Lucatorto}, Year = {1984}, Key = {Boyd84} } @article{fds318448, Author = {Boyd, RW and Gauthier, DJ and Krasinski, J and Malcuit, MS}, Title = {CONTINUOUSLY TUNABLE SUM-FREQUENCY GENERATION INVOLVING SODIUM RYDBERG STATES.}, Pages = {93-94}, Year = {1984}, Month = {January}, Key = {fds318448} } @booklet{Krasinski85, Author = {Krasinski, J and Gauthier, DJ and Malcuit, MS and Boyd, RW}, Title = {2-photon conical emission}, Journal = {Optics Communications}, Volume = {54}, Number = {4}, Pages = {241-245}, Year = {1985}, ISSN = {0030-4018}, Abstract = {A two-photon resonantly enhanced four-wave mixing (FWM) process leading to the conical emission of two new frequency components has been observed in atomic sodium vapor. A dye laser tuned close to the 3s → 3d two-photon allowed transition produces broad-band emission near the frequencies of the 3d → 3p and 3p → 3s transitions. This radiation is emitted in the forward direction in the form of cones surrounding the transmitted laser beam. The dependence of the cone angle on the emission wavelength and atomic number density is in excellent agreement with the predictions of a model that ascribes the origin of the conical emission to a phase-matched four-wave mixing process. © 1985.}, Key = {Krasinski85} } @booklet{Benda85, Author = {Benda, JA and Gauthier, DJ and Boyd, RW}, Title = {Transient sum-frequency generation in resonant three-level media}, Journal = {Physical Review A}, Volume = {32}, Number = {6}, Pages = {3461-3466}, Publisher = {American Physical Society (APS)}, Year = {1985}, Month = {January}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.32.3461}, Abstract = {Resonantly enhanced sum-frequency generation of pulsed laser radiation is treated theoretically for the case of a three-level system. The density-matrix equations of motion are solved using second-order, time-dependent perturbation theory with the inclusion of transient effects. The energy and spectrum of the generated radiation are calculated as functions of laser detunings, laser pulse lengths, and temporal overlap of the laser pulses. The tuning characteristics and output pulse characteristics are found to differ qualitatively depending on whether or not the excitation pulses satisfy the adiabatic following criteria generalized for the case of a three-level atom. © 1985 The American Physical Society.}, Doi = {10.1103/PhysRevA.32.3461}, Key = {Benda85} } @booklet{Malcuit85, Author = {Malcuit, MS and Gauthier, DJ and Boyd, RW}, Title = {Suppression of amplified spontaneous emission by the four-wave mixing process}, Journal = {Physical Review Letters}, Volume = {55}, Number = {10}, Pages = {1086-1089}, Publisher = {American Physical Society (APS)}, Year = {1985}, Month = {January}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.55.1086}, Abstract = {Two-photon-resonant excitation of the sodium 3d level can lead to the generation of new frequencies either by amplified spontaneous emission at the 3d'3p transition frequency or by a resonantly enhanced four-wave mixing process. Competition between these two processes has been observed. The four-wave mixing process can suppress amplified spontaneous emission by preventing the excitation of the 3d level due to an interference between two different pathways connecting the ground (3s) and 3d states. © 1985 The American Physical Society.}, Doi = {10.1103/PhysRevLett.55.1086}, Key = {Malcuit85} } @article{fds304565, Author = {Krasinski, J and Gauthier, DJ and Malcuit, MS and Boyd, RW}, Title = {Two-photon conical emission}, Journal = {Optics Communications}, Volume = {54}, Number = {4}, Pages = {241-245}, Publisher = {Elsevier BV}, Year = {1985}, Month = {June}, ISSN = {0030-4018}, url = {http://dx.doi.org/10.1016/0030-4018(85)90300-1}, Abstract = {A two-photon resonantly enhanced four-wave mixing (FWM) process leading to the conical emission of two new frequency components has been observed in atomic sodium vapor. A dye laser tuned close to the 3s → 3d two-photon allowed transition produces broad-band emission near the frequencies of the 3d → 3p and 3p → 3s transitions. This radiation is emitted in the forward direction in the form of cones surrounding the transmitted laser beam. The dependence of the cone angle on the emission wavelength and atomic number density is in excellent agreement with the predictions of a model that ascribes the origin of the conical emission to a phase-matched four-wave mixing process. © 1985.}, Doi = {10.1016/0030-4018(85)90300-1}, Key = {fds304565} } @article{fds44129, Author = {P. Narum and D.J. Gauthier and R.W. Boyd}, Title = {Instabilities in a self-pumped phase conjugate mirror}, Pages = {298 - 301}, Booktitle = {Optical Bistability III}, Publisher = {Springer-Verlag, Berlin}, Editor = {H.M. Gibbs and P. Mandel and N. Peyghambarian and S.D. Smith}, Year = {1986}, Key = {fds44129} } @article{fds44130, Author = {R.W. Boyd and D.J. Gauthier and M.S. Malcuit}, Title = {Instabilities in the propagation of laser beams through atomic vapors}, Pages = {334 - 336}, Booktitle = {Optical Instabilities}, Publisher = {Cambridge University Press, New York}, Editor = {R.W. Boyd and M.G. Raymer and L.M. Narducci}, Year = {1986}, Key = {fds44130} } @booklet{Gauthier86b, Author = {Gauthier, DJ and Narum, P and Boyd, RW}, Title = {Simple, compact, high-performance permanent-magnet Faraday isolator}, Journal = {Optics Letters}, Volume = {11}, Number = {10}, Pages = {623-625}, Publisher = {The Optical Society}, Year = {1986}, Month = {January}, url = {http://dx.doi.org/10.1364/OL.11.000623}, Abstract = {The design of a Faraday isolator that uses a short glass rotator rod and produces highly uniform rotation across its clear aperture is presented. The rotator rod is 19.5 mm long, and at a wavelength of 633 nm the rotation angle is 45 deg and the isolation ratio is >45 dB. © 1986 Optical Society of America.}, Doi = {10.1364/OL.11.000623}, Key = {Gauthier86b} } @article{fds246447, Author = {Boyd, RW and Gaeta, AL and Gauthier, DJ and Malcuit, MS and Narum, P}, Title = {Instabilities in four-wave mixing}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {667}, Pages = {156-162}, Publisher = {SPIE}, Year = {1986}, Month = {October}, ISBN = {0892527021}, url = {http://dx.doi.org/10.1117/12.938862}, Abstract = {Recent research on instabilites in the four-wave mixing process is summarized. The four-wave mixing process can cause a laser beam to become unstable to the growth of new frequency components as the beam propagates through a nonlinear medium. Similar instabilities can occur in more complicated optical systems such as lasers and bistable optical devices. The nature of the instability is very different for nonlinearities resulting from one- and two-photon resonances in the susceptibility describing four-wave mixing. The four wave mixing process can lead to chaotic behavior in a self-pumped phase conjugate mirror. © 1986 SPIE.}, Doi = {10.1117/12.938862}, Key = {fds246447} } @article{fds44132, Author = {M.S. Malcuit and D.J. Gauthier and J.J. Maki and R.W. Boyd}, Title = {Competition effects among nolinear optical processes}, Booktitle = {Laser Spectroscopy VIII}, Publisher = {Springer-Verlag, Berlin}, Editor = {W. Persson and S. Svanberg}, Year = {1987}, Key = {fds44132} } @booklet{Boyd87, Author = {Boyd, RW and Malcuit, MS and Gauthier, DJ and Rzaewski, K}, Title = {Competition between amplified spontaneous emission and the four-wave-mixing process}, Journal = {Physical Review A}, Volume = {35}, Number = {4}, Pages = {1648-1658}, Publisher = {American Physical Society (APS)}, Year = {1987}, Month = {January}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.35.1648}, Abstract = {Competition between amplified spontaneous emission (ASE) and the four-wave-mixing (FWM) process has been observed under conditions of two-photon resonant excitation of the sodium 3d level. The nature of the competition is that the FWM process is able to prevent the occurrence of ASE, even though the gain of the ASE process calculated in the absence of competition effects is much larger than that of FWM. The ASE is suppressed because the fields generated by the FWM process create a new excitation pathway connecting the ground and 3d levels, and under quite general conditions this pathway interferes destructively with that due solely to the applied laser field. These effects are modeled theoretically by solving perturbatively the density-matrix equations of the atomic system, thereby determining the population in the upper level and the nonlinear polarization of the medium. The coupling between the various optical fields due to the nonlinear polarization is described by coupled amplitude equations. The solution to these equations predicts that when the wave-vector mismatch is not too large the fields evolve spatially to reach steady-state values, and that the population excited to the 3d level by the total steady-state optical field is much smaller than that due to the incident laser field alone. We have observed experimentally the suppression of ASE by FWM and have observed that this suppression does not occur when the medium is excited with counterpropagating beams that cannot efficiently excite the FWM process. In addition, we have conducted a series of experiments that shows that the degree of suppression of ASE depends on the intensity and focusing characteristics of the incident laser as expected on the basis of our theoretical model. © 1987 The American Physical Society.}, Doi = {10.1103/PhysRevA.35.1648}, Key = {Boyd87} } @booklet{Gauthier87, Author = {Gauthier, DJ and Narum, P and Boyd, RW}, Title = {Observation of deterministic chaos in a phase-conjugate mirror}, Journal = {Physical Review Letters}, Volume = {58}, Number = {16}, Pages = {1640-1643}, Publisher = {American Physical Society (APS)}, Year = {1987}, Month = {January}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.58.1640}, Abstract = {Deterministic chaos in the intensity of the beam produced by a barium titanate self-pumped phase-conjugate mirror has been observed. The correlation exponent of the strange attractor is found to depend on the crystal orientation and to lie within the range 1.2 to 2.4, and the order-two Renyi entropy is found to increase with increasing laser intensity and to be as large as 22 bits/sec. A standard model of self-pumped phase conjugation due to four-wave mixing has been generalized to include time dependence. This model predicts frequency shifts and chaotic behavior for the reflectivity. © 1987 The American Physical Society.}, Doi = {10.1103/PhysRevLett.58.1640}, Key = {Gauthier87} } @booklet{Malcuit87, Author = {Malcuit, MS and Gauthier, DJ and Boyd, RW}, Title = {Competition between four-wave mixing and amplified spontaneous emission}, Journal = {Hyperfine Interactions}, Volume = {37}, Number = {1-4}, Pages = {125-139}, Publisher = {Springer Nature}, Year = {1987}, Month = {December}, ISSN = {0304-3843}, url = {http://dx.doi.org/10.1007/BF02395707}, Abstract = {There has recently been considerable interest in nonlinear optical interactions in which two different processes compete with one another. In this paper, we review some recent work in this area, and describe the results of our own investigation of competition between four-wave mixing and amplified spontaneous emission. We find that under two-photon excitation of the sodium 3d level, new optical frequency components can be generated either by amplified spontaneous emission at the 3d→3p transition frequency or by a resonantly enhanced four-wave mixing process. We have observed competition between these two processes, resulting in the suppression of amplified spontaneous emission. The transfer of population to the 3d level is inhibited by the destructive interference between two different pathways connecting the ground and upper levels. © 1987 J.C. Baltzer A.G. Scientific Publishing Company.}, Doi = {10.1007/BF02395707}, Key = {Malcuit87} } @booklet{Malcuit88, Author = {Malcuit, MS and Gauthier, DJ and Boyd, RW}, Title = {Vector phase conjugation by two-photon-resonant degenerate four-wave mixing}, Journal = {Optics Letters}, Volume = {13}, Number = {8}, Pages = {663-665}, Publisher = {The Optical Society}, Year = {1988}, Month = {January}, url = {http://dx.doi.org/10.1364/OL.13.000663}, Abstract = {We have studied the polarization properties of phase conjugation by degenerate four-wave mixing resonantly enhanced by the sodium 3S1/2 → 6S1/2 two-photon-allowed transition. As predicted by third-order theories, this interaction leads to simultaneous conjugation of the optical wave front and state of polarization (vector phase conjugation) when the pump intensities are sufficiently weak. However, qualitatively different polarization behavior is observed for pump intensities near or above the two-photon saturation intensity. © 1988, Optical Society of America.}, Doi = {10.1364/OL.13.000663}, Key = {Malcuit88} } @booklet{Gauthier88, Author = {Gauthier, DJ and Malcuit, MS and Boyd, RW}, Title = {Polarization instabilities of counterpropagating laser beams in sodium vapor}, Journal = {Physical Review Letters}, Volume = {61}, Number = {16}, Pages = {1827-1830}, Publisher = {American Physical Society (APS)}, Year = {1988}, Month = {January}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.61.1827}, Abstract = {We have observed temporal instabilities in the polarizations of counterpropagating laser beams in atomic sodium vapor. For intensities slightly above the instability threshold, the polarizations fluctuate periodically. For higher intensities, the fluctuations are chaotic and the system evolves on a strange attractor whose fractal dimension increases with increasing laser intensity. © 1988 The American Physical Society.}, Doi = {10.1103/PhysRevLett.61.1827}, Key = {Gauthier88} } @article{fds44133, Author = {D.J. Gauthier and M.S. Malcuit and R.W. Boyd}, Title = {Bistability and chaos of counterpropagating laser beams}, Pages = {395 - 399}, Booktitle = {Coherence and Quantum Optics VI}, Editor = {J.H. Eberly and L. Mandel and E. Wolf}, Year = {1989}, Key = {fds44133} } @article{fds44134, Author = {R.W. Boyd and A.L. Gaeta and D.J. Gauthier and M.S. Malcuit}, Title = {Bistability and chaotic instabilities of laser beams counterpropagating through sodium vapor}, Pages = {164 - 166}, Booktitle = {Laser Spectroscopy IX}, Editor = {M.S. Feld and J.E. Thomas and A. Mooradian}, Year = {1989}, Key = {fds44134} } @booklet{Kauranen89, Author = {Kauranen, M and Gauthier, DJ and Malcuit, MS and Boyd, RW}, Title = {Polarization properties of optical phase conjugation by two-photon resonant degenerate four-wave mixing}, Journal = {Physical Review A}, Volume = {40}, Number = {4}, Pages = {1908-1917}, Publisher = {American Physical Society (APS)}, Year = {1989}, Month = {January}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.40.1908}, Abstract = {We develop a semiclassical theory of the polarization properties of phase conjugation by two-photon resonant degenerate four-wave mixing. The theory includes the effects of saturation by the pump waves. We solve the density-matrix equations of motion in steady state for a nonlinear medium consisting of stationary atoms with a ground and excited state connected by two-photon transitions. As an illustration of the general results, we consider an S0S0 two-photon transition, which is known to lead to perfect polarization conjugation in the limit of third-order theory. We show that the fidelity of the polarization-conjugation process is degraded for excessively large pump intensities. The degradation can occur both due to transfer of population to the excited state and due to nonresonant Stark shifts. Theoretical results are compared to those of a recent experiment [Malcuit, Gauthier, and Boyd, Opt. Lett. 13, 663 (1988)]. © 1989 The American Physical Society.}, Doi = {10.1103/PhysRevA.40.1908}, Key = {Kauranen89} } @booklet{Gauthier89, Author = {Gauthier, DJ and Boyd, RW and Jungquist, RK and Lisson, JB and Voci, LL}, Title = {Phase-conjugate Fizeau interferometer}, Journal = {Optics Letters}, Volume = {14}, Number = {6}, Pages = {323-325}, Publisher = {The Optical Society}, Year = {1989}, Month = {March}, url = {http://dx.doi.org/10.1364/OL.14.000323}, Abstract = {We describe a phase-conjugate interferometer that consists of a partially transmitting conventional mirror placed in front of and in close proximity to a phase-conjugate mirror. The interferometer is self-referencing, compact, and insensitive to environmental disturbances, provides twice the sensitivity of conventional (nonphase-conjugate) interferometers, and produces a direct representation of an incident wave front. We have constructed such a device using internally self-pumped phase conjugation in barium titanate and have used the device to characterize the wave front produced by an aberrated optical system. © 1989 Optical Society of America.}, Doi = {10.1364/OL.14.000323}, Key = {Gauthier89} } @article{fds322484, Author = {Boyd, RW and Gauthier, DJ and Kauranen, M and Malcuit, MS and Tompkin, WR}, Title = {Polarization properties of phase conjugation by degenerate four-wave mixing in saturable absorbers}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {1060}, Pages = {58-65}, Publisher = {SPIE}, Year = {1989}, Month = {August}, url = {http://dx.doi.org/10.1117/12.951728}, Abstract = {Dye molecules held rigidly in solid hosts display unusual polarization properties that can be exploited to produce nearly perfect vector phase conjugation with high sensitivity. © SPIE.}, Doi = {10.1117/12.951728}, Key = {fds322484} } @article{fds246301, Author = {Kauranen, M and Gauthier, DJ and Malcuit, MS and Boyd, RW}, Title = {Theory of vector phase conjugation by two-photon-resonant degenerate four-wave mixing}, Pages = {106-107}, Year = {1989}, Month = {December}, Abstract = {A semiclassical theory of phase conjugation by two-photon-resonant degenerate four-wave mixing has been developed. The theory treats both the tensor nature of the interaction and the effects of saturation of the atomic system. An S → S two-photon transition has been considered, and the coupling strength for the generation of the conjugate wave has been calculated for arbitrary pump and probe beam polarizations and arbitrary pump intensities. Results for high and low intensities are shown and discussed.}, Key = {fds246301} } @booklet{Zhu90, Author = {Zhu, Y and Wu, Q and Lezama, A and Gauthier, DJ and Mossberg, TW}, Title = {Resonance fluorescence of two-level atoms under strong bichromatic excitation}, Journal = {Physical Review A}, Volume = {41}, Number = {11}, Pages = {6574-6576}, Publisher = {American Physical Society (APS)}, Year = {1990}, Month = {January}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.41.6574}, Abstract = {We have measured the emission spectrum of two-level-like Ba atoms driven by two strong, equal-amplitude fields with frequency separation 2. The spectrum consists of a series of peaks with an essentially constant spacing and alternating linewidths. These features differ qualitatively from the characteristic triplet spectrum observed in the case of strong monochromatic excitation. Certain features of the observed spectrum such as its comblike structure can be motivated in terms of the energy spectrum of atom bichromatic-field product states. Other features, such as the alternating linewidths, require more subtle analysis. © 1990 The American Physical Society.}, Doi = {10.1103/PhysRevA.41.6574}, Key = {Zhu90} } @booklet{Gauthier90, Author = {Gauthier, DJ and Malcuit, MS and Gaeta, AL and Boyd, RW}, Title = {Polarization bistability of counterpropagating laser beams}, Journal = {Physical Review Letters}, Volume = {64}, Number = {15}, Pages = {1721-1724}, Publisher = {American Physical Society (APS)}, Year = {1990}, Month = {January}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.64.1721}, Abstract = {We have observed bistability in the states of polarization of laser beams counterpropagating through sodium vapor. No external feedback is provided; the beams interact solely through four-wave mixing processes. © 1990 The American Physical Society.}, Doi = {10.1103/PhysRevLett.64.1721}, Key = {Gauthier90} } @booklet{Zhu90a, Author = {Zhu, Y and Gauthier, DJ and Morin, SE and Wu, Q and Carmichael, HJ and Mossberg, TW}, Title = {Vacuum Rabi splitting as a feature of linear-dispersion theory: Analysis and experimental observations}, Journal = {Physical Review Letters}, Volume = {64}, Number = {21}, Pages = {2499-2502}, Publisher = {American Physical Society (APS)}, Year = {1990}, Month = {January}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.64.2499}, Abstract = {The spectral and temporal response of an optical cavity resonantly coupled to an ensemble of barium atoms has been investigated experimentally. The empty-cavity trnasmission resonances are found to split in the presence of the atoms and, under these conditions, the cavitys temporal response is found to be oscillatory. These effects may be viewed as a manifestation of a vacuum-field Rabi splitting, or as a simple consequence of the linear absorption and dispersion of the intracavity atoms. © 1990 The American Physical Society.}, Doi = {10.1103/PhysRevLett.64.2499}, Key = {Zhu90a} } @article{fds246302, Author = {Gauthier, DJ and Zhu, Y and Morin, SE and Wu, Q and Carmichael, HJ and Mossberg, TW}, Title = {Time- and frequency-domain studies of multiatom vacuum Rabi splitting in a large cavity}, Journal = {Xvii International Conference on Quantum Electronics. Digest Of}, Pages = {186-187}, Year = {1990}, Month = {December}, Abstract = {The first frequency- and time-domain observations of the resonant large cavity and multiatom vacuum Rabi splitting are reported. The transmission as a function of frequency (time) of a weak CW (pulsed) laser beam through a high-finesse (500), 1-cm, 7.5-GHz, free-spectral-range, confocal Fabry-Perot cavity containing 850-1400 barium atoms has been measured. A plot of cavity intensity throughput as a function of the frequency of the CW input beam is shown and discussed. The spectrum, which represents the transmission function of the cavity, provides a way to calculate the transient response of the atom-cavity transmission based on linear systems theory. Equivalently, the same transient response of the transmission is predicted in terms of the quantized atom-cavity interaction. In either case, a damped oscillatory response is expected. To study this case, the temporal profile of a weak, smooth, ≅8-ns pulse after transmission through the cavity in a case where the number of Ba atoms within the cavity resulted in a large frequency-domain splitting was recorded. Excellent agreement with linear systems theory is observed.}, Key = {fds246302} } @booklet{Agarwal91, Author = {Agarwal, GS and Zhu, Y and Gauthier, DJ and Mossberg, TW}, Title = {Spectrum of radiation from two-level atoms under intense bichromatic excitation}, Journal = {Journal of the Optical Society of America B}, Volume = {8}, Number = {5}, Pages = {1163-1167}, Publisher = {The Optical Society}, Year = {1991}, Month = {January}, url = {http://dx.doi.org/10.1364/JOSAB.8.001163}, Abstract = {We develop a theoretical framework for calculating the spectrum of resonance fluorescence emitted by twolevel atoms that are excited by a strong bichromatic field. The dressed states for the two-level system that is interacting with a fully modulated field are identified, and the spectral features are interpreted in terms of transitions among these dressed states. © 1991 Optical Society of America.}, Doi = {10.1364/JOSAB.8.001163}, Key = {Agarwal91} } @booklet{Mossberg91, Author = {Mossberg, TW and Lewenstein, M and Gauthier, DJ}, Title = {Trapping and cooling of atoms in a vacuum perturbed in a frequency-dependent manner}, Journal = {Physical Review Letters}, Volume = {67}, Number = {13}, Pages = {1723-1726}, Publisher = {American Physical Society (APS)}, Year = {1991}, Month = {January}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.67.1723}, Abstract = {We show that light-induced mechanical forces that act on atoms may be significantly enhanced and acquire novel physical character when the electromagnetic reservoir which mediates the atomic relaxation is colored (i.e., frequency dependent). © 1991 The American Physical Society.}, Doi = {10.1103/PhysRevLett.67.1723}, Key = {Mossberg91} } @booklet{Gauthier91, Author = {Gauthier, DJ and Zhu, Y and Mossberg, TW}, Title = {Observation of linewidth narrowing due to coherent stabilization of quantum fluctuations}, Journal = {Physical Review Letters}, Volume = {66}, Number = {19}, Pages = {2460-2463}, Publisher = {American Physical Society (APS)}, Year = {1991}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevLett.66.2460}, Abstract = {Quantum fluctuations of an optical transition moment are observed to be suppressed by strong coherent excitation of a weak auxiliary transition. The stabilization is manifest through the appearance of subnatural linewidths in the resonance fluorescence spectrum and is due to coherent mixing of atomic states. Our results are in quantitative agreement with the predictions of L. M. Narducci et al. [Phys. Rev. A 42, 1630 (1990)]. © 1991 The American Physical Society.}, Doi = {10.1103/PhysRevLett.66.2460}, Key = {Gauthier91} } @booklet{Zhang91, Author = {Zhang, JM and Gauthier, DJ and Huang, J and Mossberg, TW}, Title = {Use of phase-noisy laser fields in the storage of optical pulse shapes in inhomogeneously broadened absorbers}, Journal = {Optics Letters}, Volume = {16}, Number = {2}, Pages = {103-105}, Publisher = {The Optical Society}, Year = {1991}, Month = {January}, url = {http://dx.doi.org/10.1364/OL.16.000103}, Abstract = {It has been demonstrated [see, e.g., W.R. Babbitt and T. W. Mossberg, Opt. Commun. 65, 185 (1988)] that coherent optical processes can be employed to store and reproduce temporal sequences of optical data, thereby providing a mechanism for advanced optical memories. We find that excitation pulse phase noise can be used to extend the range of experimental conditions under which the storage process is effective and discuss the use of phase noise to achieve secure data storage. © 1991 Optical Society of America.}, Doi = {10.1364/OL.16.000103}, Key = {Zhang91} } @booklet{Gauthier92, Author = {Gauthier, DJ and Wu, Q and Morin, SE and Mossberg, TW}, Title = {Realization of a continuous-wave, two-photon optical laser}, Journal = {Physical Review Letters}, Volume = {68}, Number = {4}, Pages = {464-467}, Publisher = {American Physical Society (APS)}, Year = {1992}, Month = {January}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.68.464}, Abstract = {We report the first observation of continuous-wave two-photon lasing in the optical regime, and demonstrate that its initiation requires the injection of a trigger pulse into the laser resonator. Successful operation of the two-photon laser relies on the use of a novel gain medium consisting of laser-driven, two-level atoms and the use of a high-finesse optical cavity to isolate the two-photon gain from competing processes. Threshold conditions for laser action are in good agreement with recent theoretical predictions. © 1992 The American Physical Society.}, Doi = {10.1103/PhysRevLett.68.464}, Key = {Gauthier92} } @article{fds246295, Author = {GAUTHIER, DJ and CONCANNON, HM}, Title = {INSTABILITIES IN 2-PHOTON LASERS}, Journal = {Chaos in Optics}, Volume = {2039}, Pages = {198-205}, Publisher = {SPIE-INT SOC OPTICAL ENGINEERING}, Editor = {Roy, R}, Year = {1993}, Month = {January}, ISBN = {0-8194-1288-0}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1993BZ77H00019&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Key = {fds246295} } @booklet{Gauthier93, Author = {Gauthier, DJ}, Title = {Alternate schemes for the coherent laser control of chemical reactions}, Journal = {The Journal of Chemical Physics}, Volume = {99}, Number = {3}, Pages = {1618-1622}, Publisher = {AIP Publishing}, Year = {1993}, Month = {January}, ISSN = {0021-9606}, url = {http://dx.doi.org/10.1063/1.466180}, Abstract = {Several schemes are presented for the coherent laser control of chemical reactions. They are based on the principle of interference between quantum mechanical excitation pathways first proposed by Brumer and Shapiro [Acc. Chem. Res. 22, 407 (1989)]. The conclusion that these schemes may by useful for coherent laser control is based on the fact that, for each of the schemes, the quantum mechanical interference effect has been observed previously in nonlinear optical experiments; however, no attempt to control the interference was attempted in these experiments. © 1993 American Institute of Physics.}, Doi = {10.1063/1.466180}, Key = {Gauthier93} } @article{fds246456, Author = {Concannon, HM and Gauthier, DJ}, Title = {Recent advances in two-photon lasers}, Journal = {Condensed Matter News}, Volume = {3}, Pages = {7}, Year = {1994}, Key = {fds246456} } @article{fds44136, Author = {D.J. Gauthier and H.M. Concannon}, Title = {The two-photon laser}, Pages = {365 - 384}, Booktitle = {Nonlinear Spectroscopy of Solids: Advances and Applications}, Publisher = {Plenum Press, New York}, Editor = {B. Di Bartolo and B. Bowlby}, Year = {1994}, Key = {fds44136} } @article{fds246297, Author = {GAUTHIER, DJ and CONCANNON, HM}, Title = {THE 2-PHOTON LASER}, Journal = {Nonlinear Spectroscopy of Solids}, Volume = {339}, Pages = {365-384}, Publisher = {PLENUM PRESS DIV PLENUM PUBLISHING CORP}, Editor = {DiBartolo, B}, Year = {1994}, Month = {January}, ISBN = {0-306-44916-1}, ISSN = {0258-1221}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1994BD26M00009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Key = {fds246297} } @booklet{Wu94a, Author = {Wu, Q and Gauthier, DJ and Mossberg, TW}, Title = {Phase-sensitive dynamics of bichromatically driven two-level atoms}, Journal = {Physical Review A}, Volume = {49}, Number = {3}, Pages = {R1519-R1522}, Publisher = {American Physical Society (APS)}, Year = {1994}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.49.R1519}, Abstract = {Observations of qualitatively different coherent transient phenomena associated with bichromatic optical excitation are reported. The effects demonstrated include the control of atomic dynamics through a variation of the initial relative phase of the driving fields and the polarization of population within atom-field dressed states. The dynamics observed are fundamentally more complex than those characteristic of monochromatically driven atoms. © 1994 The American Physical Society.}, Doi = {10.1103/PhysRevA.49.R1519}, Key = {Wu94a} } @booklet{Gauthier94, Author = {GAUTHIER, DJ}, Title = {THE DYNAMICS OF OPTICAL-SYSTEMS - A RENAISSANCE OF THE 1990S}, Journal = {Nonlinear Science Today}, Volume = {4}, Number = {2}, Pages = {1-+}, Publisher = {SPRINGER}, Year = {1994}, Month = {January}, ISSN = {0938-9008}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1994PV93700001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Key = {Gauthier94} } @booklet{Wu94, Author = {Wu, Q and Gauthier, DJ and Mossberg, TW}, Title = {Optical resonance and coherent transients in dressed atomic systems}, Journal = {Physical Review A}, Volume = {50}, Number = {2}, Pages = {1474-1478}, Publisher = {American Physical Society (APS)}, Year = {1994}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.50.1474}, Abstract = {We experimentally investigate the transient dynamics of two-level atoms driven by a bichromatic optical excitation field when the bichromatic field is configured to contain a strong resonant component and a weaker nonresonant perturber component. We concentrate on the experimental situation in which the two-level atoms are prepared in an eigenstate (dressed state) of the coupled atom-resonant field system prior to exposure to the perturber field. We experimentally demonstrate perturber-field-induced, optical nutation of the dressed-state populations. We show how nutation of the dressed-state populations manifests itself in the fluorescence signal of the transiently driven atoms. We observe that the detuning of the perturber field from transitions between the dressed states of the atom-resonant field system plays the same role in determining the character of the dressed-state optical nutation as the atom-field detuning in the case of the ordinary optical nutation of atomic populations. Our experiments demonstrate the utility of the dressed-atom picture in understanding the complex dynamics of bichromatically driven atoms in a variety of circumstances. © 1994 The American Physical Society.}, Doi = {10.1103/PhysRevA.50.1474}, Key = {Wu94} } @booklet{Concannon94, Author = {Concannon, HM and Gauthier, DJ}, Title = {Simple rate-equation model for two-photon lasers.}, Journal = {Optics Letters}, Volume = {19}, Number = {7}, Pages = {472-474}, Year = {1994}, Month = {April}, url = {http://dx.doi.org/10.1364/ol.19.000472}, Abstract = {We present a rate-equation model for two-photon lasers that, despite its simplicity, captures the essential physics of their behavior and affords an intuitive understanding of their novel threshold and stability behavior. We use the model to investigate the steady-state behavior of the laser, explore the stability of the steady-state solutions, and predict the injected pulse strength needed to initiate lasing.}, Doi = {10.1364/ol.19.000472}, Key = {Concannon94} } @booklet{Gauthier94a, Author = {Gauthier, DJ and Sukow, DW and Concannon, HM and Socolar, JE}, Title = {Stabilizing unstable periodic orbits in a fast diode resonator using continuous time-delay autosynchronization.}, Journal = {Physical Review E Statistical, Nonlinear, and Soft Matter Physics}, Volume = {50}, Number = {3}, Pages = {2343-2346}, Year = {1994}, Month = {September}, ISSN = {1063-651X}, url = {http://www.ncbi.nlm.nih.gov/pubmed/9962244}, Doi = {10.1103/physreve.50.2343}, Key = {Gauthier94a} } @booklet{Hooper94, Author = {Hooper, BA and Gauthier, DJ and Madey, JM}, Title = {Fourth-harmonic generation in a single lithium niobate-crystal with cascaded second-harmonic generation.}, Journal = {Applied Optics}, Volume = {33}, Number = {30}, Pages = {6980-6984}, Year = {1994}, Month = {October}, ISSN = {0003-6935}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1994PN17900010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {Tunable second- and fourth-harmonic radiation was generated in a single 1-cm-long lithium niobate (LiNbO(3)) crystal with the Mark III infrared free electron laser at Duke University. The fundamental laser radiation was tuned from 2 to 2.5 µm, yielding 1-1.25-µm radiation (second harmonic) and 0.5-0.625-µm radiation (fourth harmonic). A fundamental-second-harmonic energy conversion efficiency of 66% and a fundamental-fourth-harmonic energy conversion efficiency of 3.3 × 10(-6) were measured. The maximum energy in the fourth harmonic was 3.3 nJ.}, Doi = {10.1364/ao.33.006980}, Key = {Hooper94} } @booklet{Socolar94, Author = {Socolar, JE and Sukow, DW and Gauthier, DJ}, Title = {Stabilizing unstable periodic orbits in fast dynamical systems.}, Journal = {Physical Review E Statistical, Nonlinear, and Soft Matter Physics}, Volume = {50}, Number = {4}, Pages = {3245-3248}, Year = {1994}, Month = {October}, ISSN = {1063-651X}, url = {http://www.ncbi.nlm.nih.gov/pubmed/9962372}, Doi = {10.1103/physreve.50.3245}, Key = {Socolar94} } @article{fds44137, Author = {D.J. Gauthier and H.M. Concannon}, Title = {Observation of 30% continuous-wave two-photon amplification}, Pages = {501 - 502}, Booktitle = {Coherence and Quantum Optics VIII}, Publisher = {Plenum, New York}, Editor = {J.H. Eberly and L. Mandel and E. Wolf}, Year = {1995}, Key = {fds44137} } @article{fds246303, Author = {Gauthier, DJ and Sukow, DW}, Title = {Controlling chaos in fast optical systems}, Journal = {Conference Proceedings Lasers and Electro Optics Society Annual Meeting Leos}, Volume = {1}, Pages = {33-34}, Year = {1995}, Month = {December}, Abstract = {Chaotic systems can be stabilized by applying only small perturbations to some accessible system parameter. The OGY scheme and its variations have been used successfully to control the dynamics of lasers. This paper describes alternative implementations of the OGY scheme that efficiently stabilize the unstable periodic orbits (UPO's) and unstable steady-states (USS's) of fast dynamical systems using small perturbations. The schemes are well suited for controlling instabilities in high-speed optical systems such as diode lasers.}, Key = {fds246303} } @article{fds246294, Author = {Gauthier, DJ and Concannon, HM}, Title = {Observation of 30% continuous-wave two-photon optical amplification}, Journal = {Coherence and Quantum Optics Vii}, Pages = {501-502}, Publisher = {PLENUM PRESS DIV PLENUM PUBLISHING CORP}, Editor = {Eberly, JH and Mandel, L and Wolf, E}, Year = {1996}, Month = {January}, ISBN = {0-306-45314-2}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1996BG08Q00124&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Key = {fds246294} } @booklet{Venkataramani96, Author = {Venkataramani, SC and Hunt, BR and Ott, E and Gauthier, DJ and Bienfang, JC}, Title = {Transitions to bubbling of chaotic systems}, Journal = {Physical Review Letters}, Volume = {77}, Number = {27}, Pages = {5361-5364}, Publisher = {American Physical Society (APS)}, Year = {1996}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevLett.77.5361}, Abstract = {Certain dynamical systems exhibit a phenomenon called bubbling, whereby small perturbations induce intermittent bursting. In this Letter we show that, as a parameter is varied through a critical value, the transition to bubbling can be “hard” (the bursts appear abruptly with large amplitude) or “soft” (the maximum burst amplitude increases continuously from zero), and that the presence or absence of symmetry in the unperturbed system has a fundamental effect on these transitions. These results are confirmed by numerical and physical experiments. © 1996 The American Physical Society.}, Doi = {10.1103/PhysRevLett.77.5361}, Key = {Venkataramani96} } @booklet{Gauthier96, Author = {Gauthier, DJ and Bienfang, JC}, Title = {Intermittent loss of synchronization in coupled chaotic oscillators: Toward a new criterion for high-quality synchronization}, Journal = {Physical Review Letters}, Volume = {77}, Number = {9}, Pages = {1751-1754}, Publisher = {American Physical Society (APS)}, Year = {1996}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevLett.77.1751}, Abstract = {We observe incomplete synchronization of coupled chaotic oscillators over a wide range of coupling strengths and coupling schemes for which high-quality synchronization is expected. Long intervals of high-quality synchronization are interrupted at irregular times by large, brief desynchronization events that can be attributed to “attractor bubbling,” clearly demonstrating that the standard synchronization criterion is not always useful in experiments. We suggest a simple method for rapidly selecting the coupling schemes that are most likely to produce high-quality synchronization. © 1996 The American Physical Society.}, Doi = {10.1103/PhysRevLett.77.1751}, Key = {Gauthier96} } @article{fds246454, Author = {Sukow, DW and Bleich, ME and Gauthier, DJ and Socolar, JES}, Title = {Controlling chaos in fast dynamical systems: Experimental results and theoretical analysis}, Journal = {And Invited Article in Chaos}, Volume = {7}, Pages = {560}, Year = {1997}, Key = {fds246454} } @article{fds246361, Author = {Gauthier, DJ and Brown, WJ and Gardner, JR and Vilaseca, R}, Title = {Laser beam amplification resulting from collective atomic recoil}, Journal = {Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series}, Volume = {12}, Pages = {110-111}, Year = {1997}, Month = {January}, Abstract = {The theory that large laser beam amplification resulting from the coherent driving of the atomic dipole moment is discussed. The coherent driving is expected even when the effects of the atomic recoil are ignored. The amplification occurs over a similar spectral region where large atomic recoil induced gain is predicted. The experiments of Hemmer and Lippi are discussed in light of a possible complex interplay between collective atomic recoil effects.}, Key = {fds246361} } @article{fds246362, Author = {Sukow, DW and Gauthier, DJ}, Title = {Suppression and entrainment of power-dropout events in external-cavity semiconductor lasers}, Journal = {Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series}, Volume = {12}, Pages = {181-182}, Year = {1997}, Month = {January}, Abstract = {The possibility of regulating the instability known as low-frequency fluctuations (LFF) was demonstrated by perturbing the current injected into the laser. LFF occurs when a semiconductor laser is subjected to weak or moderate feedback from a distant reflector, and it appears as irregular, spontaneous dropouts in the laser intensity. The dynamics of LFF are exceptionally complex, occurring on widely disparate time scales: the interval between dropouts can be milliseconds, the dropouts themselves have widths of approximately 50 nanoseconds, and the laser emits an erratic train of pulses of approximately 100 ps width.}, Key = {fds246362} } @article{fds246363, Author = {Brown, WJ and Gardner, JR and Gauthier, DJ}, Title = {Quantum noise properties of a saturated amplifier}, Journal = {Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series}, Volume = {12}, Pages = {143}, Year = {1997}, Month = {January}, Abstract = {The quantum noise properties of a laser beam propagating through a laser-pumped potassium vapor in a near-Doppler-free configuration was investigated. Large excess noise that peaks at approximately 12 MHz with a width of approximately 15 Mhz was observed at the lowest input power due to nonlinear optical processes which degraded the coherence properties of the strong pump beam. The use of larger input beam powers led to an increase in the bandwidth of the excess quantum noise.}, Key = {fds246363} } @article{fds246364, Author = {Gardner, JR and Brown, WJ and Gauthier, DJ and Vilaseca, R}, Title = {Collective atomic recoil and dressed-state resonances}, Journal = {Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series}, Volume = {12}, Pages = {218}, Year = {1997}, Month = {January}, Abstract = {Laser beam amplification in strongly driven potassium atoms is investigated. The pump and probe beams are tuned near the 4S 1/2 →4P 1/2 (D 1 ) transition and have linear, orthogonal polarizations. The probe beam amplification as a function of the probe-pump detuning curve is similar to that observed by Hemmer et al. The dependence of the amplification on the pump-beam intensity and tuning, and on the presence of helium or nitrogen buffer gas, is discussed.}, Key = {fds246364} } @booklet{Brown97, Author = {Brown, WJ and Gardner, JR and Gauthier, DJ and Vilaseca, R}, Title = {Amplification of laser beams counterpropagating through a potassium vapor: The effects of atomic coherence}, Journal = {Physical Review A}, Volume = {56}, Number = {4}, Pages = {3255-3261}, Publisher = {American Physical Society (APS)}, Year = {1997}, Month = {January}, ISSN = {1050-2947}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1997YA78000101&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {We observe amplification of a linearly polarized laser beam propagating through a Doppler-broadened atomic potassium vapor driven by an intense, linear and orthogonally polarized counterpropagating laser beam. The observed gain spectra are well explained by a model that incoporates only the effects of the coherent driving of the atomic dipole moment and not atomic recoil. Our results suggest that the recently reported observations of amplification and lasing using a laser-driven sodium vapor may not arise from the effects of collective atomic recoil. © 1997 The American Physical Society.}, Doi = {10.1103/PhysRevA.56.3255}, Key = {Brown97} } @booklet{Brown97a, Author = {Brown, WJ and Gardner, JR and Gauthier, DJ and Vilaseca, R}, Title = {Amplification of laser beams propagating through a collectionof strongly driven, Doppler-broadened two-level atoms}, Journal = {Physical Review A}, Volume = {55}, Number = {3}, Pages = {R1601-R1604}, Publisher = {American Physical Society (APS)}, Year = {1997}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.55.R1601}, Abstract = {We investigate theoretically the amplification of a laser beam propagating through a collection of Doppler-broadened two-level atoms driven by an intense counterpropagating laser beam. Large amplification of the beam is predicted when the pump-beam Rabi frequency is comparable to the Doppler width of the atomic transition, even without including the effects of atomic recoil. The microscopic origin of the gain can be attributed to the coherent driving of the atomic dipole moment, suggesting that amplification and lasing due to collective atomic recoil may be influenced by this process. © 1997 The American Physical Society.}, Doi = {10.1103/PhysRevA.55.R1601}, Key = {Brown97a} } @booklet{Concannon97, Author = {Concannon, HM and Brown, WJ and Gardner, JR and Gauthier, DJ}, Title = {Observation of large continuous-wave two-photon optical amplification}, Journal = {Physical Review A}, Volume = {56}, Number = {2}, Pages = {1519-1523}, Publisher = {American Physical Society (APS)}, Year = {1997}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.56.1519}, Abstract = {We observe 30% two-photon optical amplification of a probe laser-field propagating through a laser-pumped potassium vapor. This amplification is spectrally isolated and substantially larger than that of previously reported continuous-wave two-photon amplifiers. The combination of large amplification and spectral isolation of the two-photon gain feature will greatly facilitate precise studies of the photon statistics of this highly nonlinear quantum amplifier and the development and characterization of a two-photon laser based on this gain medium. We also observe spectrally-distinct three-photon amplification [Formula Presented]%) in the same system under different experimental conditions. We present a simple model of the interaction that gives qualitative agreement with our observations and explains the dependence of the two-photon gain on the various system parameters. This model predicts that the size of the two-photon gain is quite sensitive to an interference between two different quantum pathways. © 1997 The American Physical Society.}, Doi = {10.1103/PhysRevA.56.1519}, Key = {Concannon97} } @booklet{Sukow97, Author = {Sukow, DW and Gardner, JR and Gauthier, DJ}, Title = {Statistics of power-dropout events in semiconductor lasers with time-delayed optical feedback}, Journal = {Physical Review A}, Volume = {56}, Number = {5}, Pages = {R3370-R3373}, Publisher = {American Physical Society (APS)}, Year = {1997}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.56.R3370}, Abstract = {We measure experimentally the statistical distribution of time intervals between power-dropout events occurring in a semiconductor laser with time-delayed optical feedback operating in the low-frequency fluctuation regime. Near the laser threshold, the time-interval probability distribution displays a low-probability region, or dead zone, for short times, followed by a slow rise, and an exponential decay for long times. At higher injection currents, the distributions develop considerable structure. We compare our results to the predictions of approximate analytic models of the laser dynamics and find that no single model accurately captures the details of the observed distributions, indicating that our physical understanding of the long-term dynamics of the laser in this regime is less than complete. © 1997 The American Physical Society.}, Doi = {10.1103/PhysRevA.56.R3370}, Key = {Sukow97} } @article{fds246304, Author = {Sukow, DW and Bleich, ME and Gauthier, DJ and Socolar, JES}, Title = {Controlling chaos in a fast diode resonator using extended time-delay autosynchronization: Experimental observations and theoretical analysis.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {7}, Number = {4}, Pages = {560-576}, Year = {1997}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12779682}, Abstract = {We stabilize unstable periodic orbits of a fast diode resonator driven at 10.1 MHz (corresponding to a drive period under 100 ns) using extended time-delay autosynchronization. Stabilization is achieved by feedback of an error signal that is proportional to the difference between the value of a state variable and an infinite series of values of the state variable delayed in time by integral multiples of the period of the orbit. The technique is easy to implement electronically and it has an all-optical counterpart that may be useful for stabilizing the dynamics of fast chaotic lasers. We show that increasing the weights given to temporally distant states enlarges the domain of control and reduces the sensitivity of the domain of control on the propagation delays in the feedback loop. We determine the average time to obtain control as a function of the feedback gain and identify the mechanisms that destabilize the system at the boundaries of the domain of control. A theoretical stability analysis of a model of the diode resonator in the presence of time-delay feedback is in good agreement with the experimental results for the size and shape of the domain of control. (c) 1997 American Institute of Physics.}, Doi = {10.1063/1.166256}, Key = {fds246304} } @booklet{Gauthier97, Author = {Gauthier, DJ and Socolar, JES}, Title = {Dynamic control of cardiac alternans - Comment}, Journal = {Physical Review Letters}, Volume = {79}, Number = {24}, Pages = {4938-4938}, Year = {1997}, Month = {December}, ISSN = {0031-9007}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1997YL24400061&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {A Comment on the Letter by Keven Hall, et al., Phys. Rev. Lett. 78, 4518 (1997). © 1997 The American Physical Society.}, Doi = {10.1103/PhysRevLett.79.4938}, Key = {Gauthier97} } @article{fds246503, Author = {Gauthier, DJ}, Title = {Chaos comes again}, Journal = {Science}, Volume = {279}, Number = {5354}, Pages = {1156}, Year = {1998}, url = {http://dx.doi.org/10.1126/science.279.5354.1156}, Doi = {10.1126/science.279.5354.1156}, Key = {fds246503} } @article{fds4914, Author = {D.J. Gauthier}, Title = {Intermittent loss of synchronized chaos under conditions when high-quality synchronization is expected}, Pages = {383-394}, Booktitle = {Proceedings of the 4th Experimental Chaos Conference}, Publisher = {World Scientific, Singapore}, Editor = {M. Ding and W. Ditto and L. Pecora and M. Spano and S. Vohra}, Year = {1998}, Key = {fds4914} } @article{fds246365, Author = {Brown, WJ and Pfister, O and Gauthier, DJ}, Title = {New mechanism for continuous-wave two-photon amplification}, Journal = {Technical Digest European Quantum Electronics Conference}, Pages = {200-201}, Year = {1998}, Month = {January}, Abstract = {A probe-laser beam is amplified using a laser-driven, high-density potassium atomic beam in the presence of a weak magnetic field. Two σ + -polarized beams tuned near the 4S 1/2 -4P 1/2 transition form an electromagnetically induced trapped state by optically pumping the atoms in the 4S 1/2 state. Two-photon amplification of the z-polarized probe beam occurs when the atom makes a transition from the 4S 1/2 trapped state to the 4S 1/2 state in the presence of a σ - -polarized pump-beam. In this two-photon Raman process, two photons are annihilated and two z-polarized probe photons are created. Analysis of the quantum pathways reveals that they add constructively, whereas other geometries or laser beam polarizations can lead to destructive interference between pathways.}, Key = {fds246365} } @article{fds246504, Author = {Gauthier, DJ}, Title = {Controlling lasers by use of extended time-delay autosynchronization.}, Journal = {Optics Letters}, Volume = {23}, Number = {9}, Pages = {703-705}, Year = {1998}, Month = {January}, url = {http://dx.doi.org/10.1364/ol.23.000703}, Abstract = {A method is described for suppressing chaotic instabilities in lasers by use of a specific form of controlling-chaos feedback. The technique is easy to implement and requires only application of small perturbations to an accessible system parameter or variable.}, Doi = {10.1364/ol.23.000703}, Key = {fds246504} } @article{fds246505, Author = {Socolar, JES and Gauthier, DJ}, Title = {Analysis and comparison of multiple-delay schemes for controlling unstable fixed points of discrete maps}, Journal = {Physical Review E Statistical, Nonlinear, and Soft Matter Physics}, Volume = {57}, Number = {6}, Pages = {6589-6595}, Publisher = {American Physical Society (APS)}, Year = {1998}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevE.57.6589}, Abstract = {We investigate theoretically the stabilization of a fixed point of a discrete one-dimensional nonlinear map by applying small perturbations to an accessible system parameter or variable. The size of the perturbations is determined in real time using feedback schemes incorporating only the dynamical state of the system and its state at previous iterates without making a comparison to a reference state. In particular, we compare and contrast two algorithms: extended time-delay autosynchronization, which uses an infinite series of past iterates with weights that decay by a factor of [formula presented] with each time step, and [formula presented]-time-delay autosynchronization, which uses an average of [formula presented] past iterates with equal weights. The range of feedback parameters that successfully stabilize the fixed point and the robustness of the schemes to noise are determined. It is found that the domain of control for the two schemes is similar for appropriately matched values of [formula presented] and [formula presented], and that [formula presented]-time-delay autosynchronization tends to be less sensitive to noise. © 1998 The American Physical Society.}, Doi = {10.1103/PhysRevE.57.6589}, Key = {fds246505} } @article{fds246506, Author = {Hall, GM and Bahar, S and Gauthier, DJ}, Title = {Experimental control of a chaotic point process using interspike intervals}, Journal = {Physical Review E Statistical, Nonlinear, and Soft Matter Physics}, Volume = {58}, Number = {2}, Pages = {1685-1689}, Publisher = {American Physical Society (APS)}, Year = {1998}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevE.58.1685}, Abstract = {A physical point process generated by passing a continuous, deterministic, chaotic signal through an integrate-and-fire device is controlled using proportional feedback incorporating only the time intervals between events. This system is unique in that the mean time between events can be adjusted independent of the dynamics of the underlying chaotic system. It is found that the range of feedback parameters giving rise to control as a function of the mean firing time exhibits surprisingly complex structure, and control is not possible when the mean interspike interval is comparable to or larger than the underlying system memory time. © 1998 The American Physical Society.}, Doi = {10.1103/PhysRevE.58.1685}, Key = {fds246506} } @article{fds304570, Author = {Gauthier, DJ}, Title = {Chaos has come again}, Journal = {Science (New York, N.Y.)}, Volume = {279}, Number = {5354}, Pages = {1156-1157}, Publisher = {American Association for the Advancement of Science (AAAS)}, Year = {1998}, Month = {February}, url = {http://dx.doi.org/10.1126/science.279.5354.1156}, Doi = {10.1126/science.279.5354.1156}, Key = {fds304570} } @article{fds246442, Author = {Chang, A and Bienfang, JC and Hall, GM and Gardner, JR and Gauthier, DJ}, Title = {Stabilizing unstable steady states using extended time-delay autosynchronization.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {8}, Number = {4}, Pages = {782-790}, Year = {1998}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12779784}, Abstract = {We describe a method for stabilizing unstable steady states in nonlinear dynamical systems using a form of extended time-delay autosynchronization. Specifically, stabilization is achieved by applying a feedback signal generated by high-pass-filtering in real time the dynamical state of the system to an accessible system parameter or variables. Our technique is easy to implement, does not require knowledge of the unstable steady state coordinates in phase space, automatically tracks changes in the system parameters, and is more robust to broadband noise than previous schemes. We demonstrate the controller's efficacy by stabilizing unstable steady states in an electronic circuit exhibiting low-dimensional temporal chaos. The simplicity and robustness of the scheme suggests that it is ideally suited for stabilizing unstable steady states in ultra-high-speed systems. (c) 1998 American Institute of Physics.}, Doi = {10.1063/1.166357}, Key = {fds246442} } @article{fds246507, Author = {Hall, GM and Bahar, S and Gauthier, DJ}, Title = {The prevalence of rate-dependent dynamics in cardiac tissue}, Journal = {Phys. Rev. Lett.}, Volume = {82}, Number = {14}, Pages = {2995}, Year = {1999}, Abstract = {We explore the rate-dependent dynamic response of periodically paced bullfrog (Rana catesbeiana) cardiac muscle. Alternans (2:2 behavior) occur in 35% of animals and 2:1 ↔ 1:1 bistability in 74% of animals. In addition, we observe 2:2 ↔ 2:1 bistablility. We discuss the implications of these results for two map-based models of cardiac dynamics. The high prevalence of bistability suggests that this dynamical behavior must be accounted for in the design of closed-loop feedback protocols to stabilize cardiac dynamics. © 1999 The American Physical Society.}, Key = {fds246507} } @article{fds246367, Author = {Pfister, O and Brown, WJ and Stenner, M and Gauthier, DJ}, Title = {Experimental realization of a two-photon laser in strongly driven potassium atoms}, Journal = {Iqec, International Quantum Electronics Conference Proceedings}, Pages = {160-161}, Year = {1999}, Month = {January}, Abstract = {Novel quantum oscillators consisting of strongly driven potassium atoms contained in a high-finesse optical resonator were examined. Two-photon amplification arose from laser-driven resonant scattering between magnetic hyperfine levels. A novel configuration using different states of polarization and an orthogonal beam geometry allowed discrimination between the numerous gain mechanisms. This configuration suppressed competing phase-matched wave-mixing processes, which was crucial to realize an ideal two-photon amplifier.}, Key = {fds246367} } @article{fds246508, Author = {Pfister, O and Brown, WJ and Stenner, MD and Gauthier, DJ}, Title = {Two-photon stimulated emission in laser-driven alkali-metal atoms using an orthogonal pump-probe geometry}, Journal = {Physical Review A}, Volume = {60}, Number = {6}, Pages = {R4249-R4252}, Publisher = {American Physical Society (APS)}, Year = {1999}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.60.R4249}, Abstract = {We observe and analyze a two-photon continuous-wave optical gain mechanism designed for building a two-photon laser. The two-photon stimulated emission is spectrally isolated and resonantly enhanced using the multilevel structure of [Formula Presented] in conjunction with an alternative interaction geometry involving orthogonal beams and polarizations. The observed two-photon laser beam amplification increases linearly with low input laser beam intensity, as expected, and saturates at a gain of [Formula Presented] at high intensity. A theoretical analysis of the observations is outlined. © 1999 The American Physical Society.}, Doi = {10.1103/PhysRevA.60.R4249}, Key = {fds246508} } @article{fds304571, Author = {Martin, HG and Sonya, B and Gauthier, DJ}, Title = {Prevalence of rate-dependent behaviors in cardiac muscle}, Journal = {Physical Review Letters}, Volume = {82}, Number = {14}, Pages = {2995-2998}, Publisher = {American Physical Society (APS)}, Year = {1999}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevLett.82.2995}, Abstract = {We explore the rate-dependent dynamic response of periodically paced bullfrog (Rana catesbeiana) cardiac muscle. Alternans (2:2 behavior) occur in 35% of animals and 2:1<-->1:1 bistability in 74% of animals. In addition, we observe 2:2<-->2:1 bistablility. We discuss the implications of these results for two map-based models of cardiac dynamics. The high prevalence of bistability suggests that this dynamical behavior must be accounted for in the design of closed-loop feedback protocols to stabilize cardiac dynamics. © 1999 The American Physical Society.}, Doi = {10.1103/PhysRevLett.82.2995}, Key = {fds304571} } @article{fds246305, Author = {Oliver, RA and Krassowska, W and Hall, GM and Bahar, S and Wolf, PD and Gauthier, DJ}, Title = {Existence of bistability and correlation with arrhythmogenesis in sheep atria}, Journal = {Annual International Conference of the Ieee Engineering in Medicine and Biology Proceedings}, Volume = {1}, Pages = {157}, Year = {1999}, Month = {December}, Abstract = {This experimental study investigates the response of sheep atria to periodic pacing. In 23 trials over 6 animals, a window of bistability was observed wherein for a range of pacing periods the atria responded 1:1 or 2:1 depending on whether pacing period was increasing or decreasing. In 18 trials, non-paced activations were also observed. In 17 of those 18 trials, the non-paced activations occurred at pacing periods within or no more than 30 ms away from the window of bistability. These results suggest bistability exists in cardiac tissue and is correlated with arrhythmogenesis.}, Key = {fds246305} } @article{fds246306, Author = {Bahar, S and Hall, GM and Oliver, RA and Krassowska, W and Gauthier, DJ}, Title = {Transitions between 2:1 and 1:1 responses in cardiac muscle induced by added stimuli}, Journal = {Annual International Conference of the Ieee Engineering in Medicine and Biology Proceedings}, Volume = {1}, Pages = {258}, Year = {1999}, Month = {December}, Abstract = {We demonstrate experimentally that transitions can be induced between stable coexisting response patterns in bullfrog ventricular myocardium by means of a single pulse injected into the stimulus train. We find that two distinct ranges of stimulus timings will elicit transitions from a 1:1 state, in which one stimulus elicits one response, and a 2:1 state, in which every other stimulus elicits a response. We also observe two distinct types of 2:1→1:1 transition. These transitions are differentiated by their transient behavior while settling from one stable state into another. We characterize these transitions, and the ranges of added stimulus timings which produce them, both experimentally and with two simple models of cardiac dynamics.}, Key = {fds246306} } @article{fds246511, Author = {Blakely, JN and Gauthier, DJ}, Title = {Attractor bubbling in coupled hyperchaotic oscillators}, Journal = {International Journal of Bifurcation and Chaos}, Volume = {10}, Number = {4}, Pages = {835-846}, Publisher = {World Scientific Pub Co Pte Lt}, Year = {2000}, Month = {January}, url = {http://dx.doi.org/10.1142/s0218127400000608}, Abstract = {We investigate experimentally attractor bubbling in a system of two coupled hyperchaotic electronic circuits. The degree of synchronization over a range of coupling strengths for two different coupling schemes is measured to identify bubbling. The circuits display regimes of both attractor bubbling and high-quality synchronization. For the coupling scheme where high-quality synchronization is observed, the transition to bubbling is "soft" and its scaling with coupling strength near the transition point does not fit into the known categories of transition types. We also compare the observed behavior to several proposed criteria for estimating the regime of high-quality synchronization. It is found that none of these methods is completely satisfactory for predicting accurately the regimes of attractor bubbling and high-quality synchronization.}, Doi = {10.1142/s0218127400000608}, Key = {fds246511} } @article{fds246509, Author = {Sukow, DW and Gauthier, DJ}, Title = {Entraining power-dropout events in an external-cavity semiconductor laser using weak modulation of the injection current}, Journal = {Ieee Journal of Quantum Electronics}, Volume = {36}, Number = {2}, Pages = {175-183}, Publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, Year = {2000}, Month = {February}, url = {http://dx.doi.org/10.1109/3.823463}, Abstract = {We measure experimentally the effects of injection current modulation on the statistical distribution of time intervals between power-dropout events occurring in an external-cavity semiconductor laser operating in the low-frequency fluctuation regime. These statistical distributions are sensitive indicators of the presence of pump current modulation. Under most circumstances, we find that weak low-frequency (in the vicinity of 19 MHz) modulation of the current causes the dropouts to occur preferentially at intervals that are integral multiples of the modulation period. The dropout events can be entrained by the periodic perturbations when the modulation amplitude is large (peak-to-peak amplitude≥8% of the dc injection current). We conjecture that modulation induces a dropout when the modulation frequency is equal to the difference in frequency between a mode of the extended cavity laser and its adjacent antimode. We also find that the statistical distribution of the dropout events is unaffected by the periodic perturbations when the modulation frequency is equal to the free spectral range of the external cavity. Numerical simulations of the extended-cavity laser display qualitatively similar behavior. The relationship of these phenomena to stochastic resonance is discussed and a possible use of the modulated laser dynamics for chaos communication is described.}, Doi = {10.1109/3.823463}, Key = {fds246509} } @article{fds246512, Author = {Oliver, RA and Hall, GM and Bahar, S and Krassowska, W and Wolf, PD and Dixon-Tulloch, EG and Gauthier, DJ}, Title = {Existence of bistability and correlation with arrhythmogenesis in paced sheep atria.}, Journal = {Journal of Cardiovascular Electrophysiology}, Volume = {11}, Number = {7}, Pages = {797-805}, Year = {2000}, Month = {July}, ISSN = {1045-3873}, url = {http://www.ncbi.nlm.nih.gov/pubmed/10921797}, Abstract = {INTRODUCTION: Studies of the electrical dynamics of cardiac tissue are important for understanding the mechanisms of arrhythmias. This study uses high-frequency pacing to investigate the dynamics of sheep atria. METHODS AND RESULTS: A 504-electrode mapping plaque was affixed to the right atrium in six sheep. Cathodal pacing stimuli were delivered to the center of the plaque. Pacing period (Tp) was decreased from 275 +/- 25 msec to 75 +/- 25 msec and then increased to 230 +/- 70 msec in steps of either 5 or 10 msec. In all 21 trials in six sheep, the atrium responded 1:1 at longer Tps and 2:1 at shorter Tps. As Tp was decreased, the response switched to 2:1 at a particular Tp. Conversely, as Tp was increased, the response switched back to 1:1 at a particular Tp. Over 21 trials, the 1:1-to-2:1 and 2:1-to-1:1 transitions occurred at 119.5 +/- 18.8 msec and 130.0 +/- 19.1 msec, respectively. This hysteretic behavior yielded bistability windows, 10.5 +/- 7.2 msec wide, wherein 1:1 and 2:1 responses existed at the same Tp. In 15 trials and in all animals, idiopathic wavefronts emanating from outside the mapped region passed through the mapped region. In 13 of those trials, the idiopathic wavefronts occurred at Tps within the bistability window or within 35 msec of its upper or lower limit. CONCLUSION: Bistability windows and idiopathic wavefronts were observed and found to be correlated with each other, suggesting a connection between bistability and arrhythmogenesis.}, Doi = {10.1111/j.1540-8167.2000.tb00051.x}, Key = {fds246512} } @article{fds246510, Author = {Blakely, JN and Gauthier, DJ and Johnson, G and Carroll, TL and Pecora, LM}, Title = {Experimental investigation of high-quality synchronization of coupled oscillators.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {10}, Number = {3}, Pages = {738-744}, Year = {2000}, Month = {September}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12779423}, Abstract = {We describe two experiments in which we investigate the synchronization of coupled periodic oscillators. Each experimental system consists of two identical coupled electronic periodic oscillators that display bursts of desynchronization events similar to those observed previously in coupled chaotic systems. We measure the degree of synchronization as a function of coupling strength. In the first experiment, high-quality synchronization is achieved for all coupling strengths above a critical value. In the second experiment, no high-quality synchronization is observed. We compare our results to the predictions of the several proposed criteria for synchronization. We find that none of the criteria accurately predict the range of coupling strengths over which high-quality synchronization is observed. (c) 2000 American Institute of Physics.}, Doi = {10.1063/1.1286996}, Key = {fds246510} } @article{fds4901, Author = {D.J. Gauthier and S. Bahar and G.M. Hall}, Title = {Controlling the dynamics of cardiac muscle using small electrical stimuli}, Pages = {229 - 256}, Booktitle = {Handbook of Biological Physics, Volume 4: Neuro-informatics, Neural Modelling}, Publisher = {Elsevier, Amsterdam}, Editor = {F. Moss and S. Gielen}, Year = {2001}, Key = {fds4901} } @article{fds246308, Author = {Gauthier, DJ and Pfister, O and Brown, WJ and Stenner, MD}, Title = {Observation of polarization instabilities and chaos in a two-photon laser}, Journal = {Optics and Photonics News}, Volume = {12}, Number = {12}, Pages = {58}, Publisher = {The Optical Society}, Year = {2001}, Month = {January}, ISSN = {1047-6938}, url = {http://dx.doi.org/10.1364/OPN.12.12.000058}, Abstract = {Polarization instabilities and chaos in a two-photon laser were discussed. The power of the beam emitted from the two-photon laser resonator was measured. Results showed that it is possible to suppress the instabilities using a strong magnetic field to lift the degeneracy of the different quantum pathways.}, Doi = {10.1364/OPN.12.12.000058}, Key = {fds246308} } @article{fds322483, Author = {Stenner, MD and Gauthier, DJ}, Title = {Quantum limits to superluminal advancement}, Journal = {Technical Digest Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, Qels 2001}, Pages = {9}, Publisher = {Opt. Soc. America}, Year = {2001}, Month = {January}, ISBN = {155752663X}, url = {http://dx.doi.org/10.1109/QELS.2001.961778}, Abstract = {© 2001 Optical Soc. Of America. Summary form only given. Using intense electromagnetic fields, it is now possible to tailor the absorption, amplification, and dispersion properties of multi-level atoms. Dramatic examples include the reduction of the group velocity of a pulse of light to 17 m/s, and increasing the group velocity to values greater than c or even to negative values. The interpretation of a negative group velocity is that the peak of the pulse leaves the medium before it enters. We will discuss possible quantum limits to the advancement of the peak of a pulse propagating through a high-anomalous-dispersion medium and our experiments on pulses propagating through a dispersion-tailored potassium vapor.}, Doi = {10.1109/QELS.2001.961778}, Key = {fds322483} } @article{fds246468, Author = {Pfister, O and Brown, WJ and Stenner, MD and Gauthier, DJ}, Title = {Polarization instabilities in a two-photon laser.}, Journal = {Physical Review Letters}, Volume = {86}, Number = {20}, Pages = {4512-4515}, Year = {2001}, Month = {May}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/11384271}, Abstract = {We describe the operating characteristics of a new type of quantum oscillator that is based on a two-photon stimulated emission process. This two-photon laser consists of spin-polarized and laser-driven 39K atoms placed in a high-finesse transverse-mode-degenerate optical resonator and produces a beam with a power of approximately 0.2 microW at a wavelength of 770 nm. We observe complex dynamical instabilities of the state of polarization of the two-photon laser, which are made possible by the atomic Zeeman degeneracy. We conjecture that the laser could emit polarization-entangled twin beams if this degeneracy is lifted.}, Doi = {10.1103/physrevlett.86.4512}, Key = {fds246468} } @article{fds246307, Author = {Gauthier, DJ and Bahar, S and Hall, GM}, Title = {Chapter 7 Controlling the dynamics of cardiac muscle using small electrical stimuli}, Journal = {Handbook of Biological Physics}, Volume = {4}, Number = {C}, Pages = {229-255}, Publisher = {Elsevier}, Year = {2001}, Month = {December}, ISSN = {1383-8121}, url = {http://dx.doi.org/10.1016/S1383-8121(01)80010-5}, Doi = {10.1016/S1383-8121(01)80010-5}, Key = {fds246307} } @article{fds246496, Author = {Hall, GM and Gauthier, DJ}, Title = {Experimental control of cardiac muscle alternans}, Journal = {Physical Review Letters}, Volume = {88}, Number = {19}, Pages = {1981021-1981024}, Year = {2002}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12005667}, Abstract = {The experimental results of suppression of cardiac muscle alternans in small pieces of in vitro paced bullfrog cardiac muscle were demonstrated using a simple self-referencing scheme. A large range of physiological conditions over many animals, control was made possible and the self-referencing control protocol was automatically adjusted to changes in paceing interval. The feasibility of developing low-energy methods for maintaining normal cardiac function were suggested by the results.}, Doi = {10.1103/physrevlett.88.198102}, Key = {fds246496} } @article{fds318446, Author = {Bennink, RS and Wong, V and Marino, AM and Aronstein, DL and Boyd, RW and Stroud, CR and Lukishova, S and Gauthier, DJ}, Title = {Honeycomb pattern formation by laser-beam filamentation in atomic sodium vapor}, Journal = {Optics and Photonics News}, Volume = {13}, Number = {12}, Pages = {29}, Year = {2002}, Month = {January}, ISBN = {0780377338}, url = {http://dx.doi.org/10.1109/EQEC.2003.1313969}, Abstract = {Optical pattern formation was discussed. A single laser beam propagating without feedback through atomic sodium vapor develops a stable, regular, transverse structure was used. It was found that a three-filament near-field pattern leading to a honeycomb far-field pattern occurs at intensities near the saturation intensity.}, Doi = {10.1109/EQEC.2003.1313969}, Key = {fds318446} } @article{fds246309, Author = {Stenner, MD and Gauthier, DJ}, Title = {Induced-modulation-instabilities limit to "fast" light propagation}, Journal = {Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series}, Volume = {74}, Pages = {175}, Year = {2002}, Month = {January}, Abstract = {Induced modulation instability is discussed in the context of high-gain bichromatically-driven atomic systems and specifically in the context of fast-light pulse propagation. Practical limitations that the induced modulation instability poses on this method for creating faster-than-c pulses are outlined.}, Key = {fds246309} } @article{fds246311, Author = {Boyd, RW and Gauthier, DJ}, Title = {Chapter 6 "Slow" and "fast" light}, Journal = {Progress in Optics}, Volume = {43}, Number = {C}, Pages = {497-530}, Publisher = {Elsevier}, Year = {2002}, Month = {January}, ISSN = {0079-6638}, url = {http://dx.doi.org/10.1016/S0079-6638(02)80030-0}, Doi = {10.1016/S0079-6638(02)80030-0}, Key = {fds246311} } @article{fds246495, Author = {Fernaández-Soler, JJ and Font, JL and Vilaseca, R and Gauthier, DJ and Kul'minski, A and Pfister, O}, Title = {Two-photon amplification and lasing in laser-driven potassium atoms: Theoretical analysis}, Journal = {Physical Review A}, Volume = {65}, Number = {3}, Pages = {1-4}, Publisher = {American Physical Society (APS)}, Year = {2002}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.65.031803}, Abstract = {A semi-classical model of the interaction between two intense electromagnetic fields with fixed states of polarization and a collection of potassium atoms is introduced. The model is used to explain features of the recent two-photon amplification and lasing experiments. The model takes into account the population and coherence effects brought about by the presence of the intense drive and probe (or lasing) fields as well as the details of the hyperfine level manifolds involved in the atom-field interaction.}, Doi = {10.1103/PhysRevA.65.031803}, Key = {fds246495} } @article{fds318447, Author = {Fernaández-Soler, JJ and Font, JL and Vilaseca, R and Gauthier, DJ and Kul'minski, A and Pfister, O}, Title = {Two-photon amplification and lasing in laser-driven potassium atoms: Theoretical analysis}, Journal = {Physical Review A}, Volume = {65}, Number = {3}, Pages = {1-4}, Year = {2002}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.65.031803}, Abstract = {A semi-classical model of the interaction between two intense electromagnetic fields with fixed states of polarization and a collection of potassium atoms is introduced. The model is used to explain features of the recent two-photon amplification and lasing experiments. The model takes into account the population and coherence effects brought about by the presence of the intense drive and probe (or lasing) fields as well as the details of the hyperfine level manifolds involved in the atom-field interaction.}, Doi = {10.1103/PhysRevA.65.031803}, Key = {fds318447} } @article{fds246469, Author = {Bennink, RS and Wong, V and Marino, AM and Aronstein, DL and Boyd, RW and Stroud, CR and Lukishova, S and Gauthier, DJ}, Title = {Honeycomb pattern formation by laser-beam filamentation in atomic sodium vapor.}, Journal = {Physical Review Letters}, Volume = {88}, Number = {11}, Pages = {113901}, Year = {2002}, Month = {March}, ISSN = {0031-9007}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000174541700013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {We have observed transverse pattern formation leading to highly regular structures in both the near and far fields when a near-resonant laser beam propagates without feedback through an atomic sodium vapor. One example is a regular far-field honeycomb pattern, which results from the transformation of the laser beam within the vapor into a stable three-lobed structure with a uniform phase distribution and highly correlated power fluctuations. The predictions of a theoretical model of the filamentation process are in good agreement with these observations.}, Doi = {10.1103/physrevlett.88.113901}, Key = {fds246469} } @article{fds246513, Author = {Gauthier, DJ and Hall, GM and Oliver, RA and Dixon-Tulloch, EG and Wolf, PD and Bahar, S}, Title = {Progress toward controlling in vivo fibrillating sheep atria using a nonlinear-dynamics-based closed-loop feedback method.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {12}, Number = {3}, Pages = {952-961}, Year = {2002}, Month = {September}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12779619}, Abstract = {We describe preliminary experiments on controlling in vivo atrial fibrillation using a closed-loop feedback protocol that measures the dynamics of the right atrium at a single spatial location and applies control perturbations at a single spatial location. This study allows investigation of control of cardiac dynamics in a preparation that is physiologically close to an in vivo human heart. The spatial-temporal response of the fibrillating sheep atrium is measured using a multi-channel electronic recording system to assess the control effectiveness. In an attempt to suppress fibrillation, we implement a scheme that paces occasionally the cardiac muscle with small shocks. When successful, the inter-activation time interval is the same and electrical stimuli are only applied when the controller senses that the dynamics are beginning to depart from the desired periodic rhythm. The shock timing is adjusted in real time using a control algorithm that attempts to synchronize the most recently measured inter-activation interval with the previous interval by inducing an activation at a time projected by the algorithm. The scheme is "single-sided" in that it can only shorten the inter-activation time but not lengthen it. Using probability distributions of the inter-activation time intervals, we find that the feedback protocol is not effective in regularizing the dynamics. One possible reason for the less-than-successful results is that the controller often attempts to stimulate the tissue while it is still in the refractory state and hence it does not induce an activation. (c) 2002 American Institute of Physics.}, Doi = {10.1063/1.1494155}, Key = {fds246513} } @article{fds246494, Author = {Tolkacheva, EG and Schaeffer, DG and Gauthier, DJ and Mitchell, CC}, Title = {Analysis of the Fenton-Karma model through an approximation by a one-dimensional map.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {12}, Number = {4}, Pages = {1034-1042}, Year = {2002}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12779627}, Abstract = {The Fenton-Karma model is a simplification of complex ionic models of cardiac membrane that reproduces quantitatively many of the characteristics of heart cells; its behavior is simple enough to be understood analytically. In this paper, a map is derived that approximates the response of the Fenton-Karma model to stimulation in zero spatial dimensions. This map contains some amount of memory, describing the action potential duration as a function of the previous diastolic interval and the previous action potential duration. Results obtained from iteration of the map and numerical simulations of the Fenton-Karma model are in good agreement. In particular, the iterated map admits different types of solutions corresponding to various dynamical behavior of the cardiac cell, such as 1:1 and 2:1 patterns. (c) 2002 American Institute of Physics.}, Doi = {10.1063/1.1515170}, Key = {fds246494} } @article{fds3778, Author = {R.W. Boyd and D.J. Gauthier}, Title = {"Slow" and "Fast" Light}, Volume = {43}, Pages = {497-530}, Booktitle = {Progress in Optics}, Editor = {E. Wolf}, Year = {2002}, Month = {December}, Key = {fds3778} } @article{fds246466, Author = {Stenner, MD and Gauthier, DJ and Neifeld, MA}, Title = {The speed of information in a `fast light' optical medium}, Journal = {Nature}, Volume = {425}, Number = {6959}, Pages = {665}, Year = {2003}, url = {http://www.phy.duke.edu/research/photon/qelectron/proj/infv/}, Abstract = {One consequence of the special theory of relativity is that no signal can cause an effect outside the source light cone, the space-time surface on which light rays emanate from the source. Violation of this principle of relativistic causality leads to paradoxes, such as that of an effect preceding its cause. Recent experiments on optical pulse propagation in so-called 'fast-light' media--which are characterized by a wave group velocity upsilon(g) exceeding the vacuum speed of light c or taking on negative values--have led to renewed debate about the definition of the information velocity upsilon(i). One view is that upsilon(i) = upsilon(g) (ref. 4), which would violate causality, while another is that upsilon(i) = c in all situations, which would preserve causality. Here we find that the time to detect information propagating through a fast-light medium is slightly longer than the time required to detect the same information travelling through a vacuum, even though upsilon(g) in the medium vastly exceeds c. Our observations are therefore consistent with relativistic causality and help to resolve the controversies surrounding superluminal pulse propagation.}, Doi = {10.1038/nature02016}, Key = {fds246466} } @article{fds246502, Author = {Kul'minskii, A and Gauthier, DJ and Vilaseca, R and Fernandez Soler, JJ and Font, JL}, Title = {Polarization behavior of a cascade / two-photon lsaer in the presence of an arbitrarily directed magnetic field}, Journal = {J. Opt. B: Quantum Semiclass. Opt.}, Volume = {5}, Pages = {243}, Year = {2003}, Key = {fds246502} } @article{fds343211, Author = {Stenner, MD and Gauthier, DJ}, Title = {Pump-beam-instability limits to Raman-gain-doublet "fast-light" pulse propagation}, Journal = {Physical Review a Atomic, Molecular, and Optical Physics}, Volume = {67}, Number = {6}, Pages = {638011-638017}, Year = {2003}, Abstract = {A study was performed on pump-beam-instability limits to Raman-gain-doublet 'fast-light' pulse propagation. It was shown that the instability was attributed to the combined effects of the cross modulation instability and stimulated Raman scattering. The results showed that the fast-light pulse advancement was limited to just a few percent of the pulse width using the pulse advancement technique.}, Key = {fds343211} } @article{fds17186, Author = {D.J. Gauthier and O. Pfister and W. J. Brown and M. D. Stenner}, Title = {Dynamics of a two-photon laser}, Pages = {547-548}, Booktitle = {Coherence and Quantum Optics VIII}, Publisher = {Kluwer Academic/Plenum Publishers, New York}, Editor = {N.P. Bigelow and J.H. Eberly and C.R. Stroud and I.A. Walmsley}, Year = {2003}, Key = {fds17186} } @article{fds16317, Author = {D.J. Gauthier}, Title = {Two-photon lasers}, Volume = {45}, Pages = {205-272}, Booktitle = {Progress in Optics}, Publisher = {Elsevier, Amsterdam}, Editor = {E. Wolf}, Year = {2003}, Key = {fds16317} } @article{fds17187, Author = {D.J. Gauthier and O. Pfister and W.J. Brown and M.D. Stenner}, Title = {Polarization Dynamics of a Two-Photon Laser}, Pages = {131-136}, Booktitle = {in Coherence and Quantum Optics VIII}, Publisher = {Kluwer Academic/Plenum Publishers, New York}, Editor = {N. P. Bigelow and J. H. Eberly and C. R. Stroud and I. A. Walmsley}, Year = {2003}, Key = {fds17187} } @article{fds17188, Author = {D.J. Gauthier and M.D. Stenner}, Title = {Pulse propagation in a high-gain bichromatically-driven Raman amplifier}, Pages = {619-620}, Booktitle = {Coherence and Quantum Optics VIII}, Publisher = {Kluwer Academic/Plenum Publishers, New York}, Editor = {N. P. Bigelow and J. H. Eberly and C. R. Stroud and I. A. Walmsley}, Year = {2003}, Key = {fds17188} } @article{fds246314, Author = {Gauthier, DJ}, Title = {Chapter 4Two-photon lasers}, Journal = {Progress in Optics}, Volume = {45}, Number = {C}, Pages = {205-272}, Publisher = {Elsevier}, Year = {2003}, Month = {January}, ISSN = {0079-6638}, url = {http://dx.doi.org/10.1016/S0079-6638(03)80006-9}, Doi = {10.1016/S0079-6638(03)80006-9}, Key = {fds246314} } @article{fds246491, Author = {Fernández-Soler, JJ and Font, JL and Vilaseca, R and Gauthier, DJ and Kul’minskii, A}, Title = {Multiphoton amplification processes and quantum-path interferences in a coherently driven atomic vapor}, Journal = {Physical Review A}, Volume = {68}, Number = {4}, Pages = {13}, Publisher = {American Physical Society (APS)}, Year = {2003}, Month = {January}, ISSN = {1050-2947}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000188711400064&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {We develop a theoretical model of two-photon amplification in laser-driven potassium atoms and use it to analyze the recent experiments reported by Pfister et al. [Phys. Rev. A 60, R4249 (1999)]. The model takes into account most of the essential factors influencing the amplification process, including the atomic hyperfine structure (which makes multiphoton emission possible) and the simultaneous interaction with intense drive and probe beams with arbitrary detunings. We determine the origin and analyze the properties of different multiphoton gain resonances that appear in the light-matter interaction. In particular, the influence of the drive and probe field amplitudes and detunings on the strength and frequency of the two-photon amplification resonance is studied in detail, showing clearly the differences with respect to the behavior of single-photon or other multiphoton amplification processes. In addition, we investigate interferences between different quantum pathways originating from the hyperfine structure and determine the conditions under which they can enhance or suppress multiphoton resonances. The predictions of the model are in good agreement with the observations, indicating that it can be used to understand recent experiments on two-photon lasing reported by Pfister et al. [Phys. Rev. Lett. 86, 4512 (2001)]. © 2003 The American Physical Society.}, Doi = {10.1103/PhysRevA.68.043824}, Key = {fds246491} } @article{fds246492, Author = {Stenner, MD and Gauthier, DJ}, Title = {Pump-beam-instability limits to Raman-gain-doublet “fast-light” pulse propagation}, Journal = {Physical Review A}, Volume = {67}, Number = {6}, Pages = {7}, Publisher = {American Physical Society (APS)}, Year = {2003}, Month = {January}, ISSN = {1050-2947}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000183915200116&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {We investigate the behavior of a system for generating “fast-light” pulses in which a bichromatic Raman pumping beam is used to generate optical gain at two frequencies and a region of anomalous dispersion between them. It is expected that increasing the gain will increase the pulse advancement. However, as the gain increases, the pumping field becomes increasingly distorted, effectively limiting the pulse advancement. We observe as much as 12% of the input pump power converted to orthogonal polarization, broadening of the initially bichromatic pump field (25 MHz initial frequency separation) to more than 2.5 GHz, and a temporal collapse of the pump beam into an erratic train of sub-500-ps pulses. The instability is attributed to the combined effects of the cross modulation instability and stimulated Raman scattering. Extreme distortion of an injected pulse that should (absent the instability) experience an advancement of 21% of its width is observed. We conclude that the fast-light pulse advancement is limited to just a few percent of the pulse width using this pulse advancement technique. The limitation imposed by the instability is important because careful study of the information velocity in fast-light pulses requires that pulse advancement be large enough to distinguish the velocities of different pulse features. Possible methods for achieving pulse advancement by avoiding the distortion caused by the instability are discussed. © 2003 The American Physical Society.}, Doi = {10.1103/PhysRevA.67.063801}, Key = {fds246492} } @article{fds304564, Author = {Tolkacheva, EG and Schaeffer, DG and Gauthier, DJ and Krassowska, W}, Title = {Condition for alternans and stability of the 1:1 response pattern in a “memory” model of paced cardiac dynamics}, Journal = {Physical Review E Statistical, Nonlinear, and Soft Matter Physics}, Volume = {67}, Number = {3}, Pages = {10}, Year = {2003}, Month = {January}, ISSN = {1539-3755}, url = {http://dx.doi.org/10.1103/PhysRevE.67.031904}, Abstract = {We analyze a mathematical model of paced cardiac muscle consisting of a map relating the duration of an action potential to the preceding diastolic interval as well as the preceding action potential duration, thereby containing some degree of “memory.” The model displays rate-dependent restitution so that the dynamic and S1-S2 restitution curves are different, a manifestation of memory in the model. We derive a criterion for the stability of the 1:1 response pattern displayed by this model. It is found that the stability criterion depends on the slope of both the dynamic and S1-S2 restitution curves, and that the pattern can be stable even when the individual slopes are greater or less than one. We discuss the relation between the stability criterion and the slope of the constant-BCL restitution curve. The criterion can also be used to determine the bifurcation from the 1:1 response pattern to alternans. We demonstrate that the criterion can be evaluated readily in experiments using a simple pacing protocol, thus establishing a method for determining whether actual myocardium is accurately described by such a mapping model. We illustrate our results by considering a specific map recently derived from a three-current membrane model and find that the stability of the 1:1 pattern is accurately described by our criterion. In addition, a numerical experiment is performed using the three-current model to illustrate the application of the pacing protocol and the evaluation of the criterion. © 2003 The American Physical Society.}, Doi = {10.1103/PhysRevE.67.031904}, Key = {fds304564} } @article{fds324415, Author = {Fernández-Soler, JJ and Font, JL and Vilaseca, R and Gauthier, DJ}, Title = {Multi-photon gain resonances and associated lasing in coherently-driven potassium atoms}, Journal = {2003 European Quantum Electronics Conference, Eqec 2003}, Pages = {46}, Publisher = {IEEE}, Year = {2003}, Month = {January}, ISBN = {0780377338}, url = {http://dx.doi.org/10.1109/EQEC.2003.1313903}, Abstract = {This study presents a more complete and wider ranging theoretical study of the amplification and lasing possibilities in alkaline atoms that takes advantage of the multiplicity of hyperfine and magnetic sublevels involved in the 39K 4S1/2-4P1/2 transition. Using drive and probe fields of appropriate polarizations and propagation directions, and optically pumped atoms, (n+m) multi-photon resonances involving absorption of n drive photons and simultaneous emission of m probe photons can be generated. Theoretical predictions are in good agreement with experimental findings.}, Doi = {10.1109/EQEC.2003.1313903}, Key = {fds324415} } @article{fds324416, Author = {Gauthier, DJ}, Title = {Instability limits to "fast light" optical pulse propagation}, Journal = {2003 European Quantum Electronics Conference, Eqec 2003}, Pages = {117}, Publisher = {IEEE}, Year = {2003}, Month = {January}, ISBN = {0780377338}, url = {http://dx.doi.org/10.1109/EQEC.2003.1313974}, Abstract = {This work demonstrates a novel experimental configuration that uses two potassium vapor cells, each of which is pumped by a single monochromatic beam, to suppress modulation instability. The linear dispersive properties of the combined system gives rise to fast light (similar to dispersion management in optical telecommunication systems), but the induced modulation instability cannot occur because no atom experience the combined effect of both pump frequencies. Results also show the electronic power spectrum of the detected fluctuations in the transmitted bichromatic pump beam, optical pulse propagation through a cell of potassium atoms pumped by a bichromatic field, and a large fast-light pulse advancement using the two-zone setup.}, Doi = {10.1109/EQEC.2003.1313974}, Key = {fds324416} } @article{fds340374, Author = {Bennink, RS and Wong, V and Marino, AM and Aronstein, DL and Boyd, RW and Stroud, CR and Lukishova, S and Gauthier, DJ}, Title = {Honeycomb pattern formation by laser-beam filamentation in atomic sodium vapor}, Journal = {2003 European Quantum Electronics Conference, Eqec 2003}, Pages = {112}, Publisher = {IEEE}, Year = {2003}, Month = {January}, ISBN = {0780377338}, url = {http://dx.doi.org/10.1109/EQEC.2003.1313969}, Abstract = {This study presents examples of observed optical pattern formation in which a single laser beam propagating through atomic sodium vapor without feedback develops a stable, regular transverse structure. In particular, a three-filament near-field pattern leading to a honeycomb far-field pattern occurs at intensities near the saturation intensity and at powers larger than (but of the order of magnitude of) the critical power for self-focusing. The three-filament pattern has a uniform phase profile and strongly correlated power fluctuations, which suggest that it is perhaps a quantum image. These observations are also found to be in good agreement with numerical simulations of filamentation in a two-level atomic medium.}, Doi = {10.1109/EQEC.2003.1313969}, Key = {fds340374} } @article{fds246493, Author = {Tolkacheva, EG and Schaeffer, DG and Gauthier, DJ and Krassowska, W}, Title = {Condition for alternans and stability of the 1:1 response pattern in a "memory" model of paced cardiac dynamics.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {67}, Number = {3 Pt 1}, Pages = {031904}, Year = {2003}, Month = {March}, ISSN = {1539-3755}, url = {http://www.ncbi.nlm.nih.gov/pubmed/12689098}, Abstract = {We analyze a mathematical model of paced cardiac muscle consisting of a map relating the duration of an action potential to the preceding diastolic interval as well as the preceding action potential duration, thereby containing some degree of "memory." The model displays rate-dependent restitution so that the dynamic and S1-S2 restitution curves are different, a manifestation of memory in the model. We derive a criterion for the stability of the 1:1 response pattern displayed by this model. It is found that the stability criterion depends on the slope of both the dynamic and S1-S2 restitution curves, and that the pattern can be stable even when the individual slopes are greater or less than one. We discuss the relation between the stability criterion and the slope of the constant-BCL restitution curve. The criterion can also be used to determine the bifurcation from the 1:1 response pattern to alternans. We demonstrate that the criterion can be evaluated readily in experiments using a simple pacing protocol, thus establishing a method for determining whether actual myocardium is accurately described by such a mapping model. We illustrate our results by considering a specific map recently derived from a three-current membrane model and find that the stability of the 1:1 pattern is accurately described by our criterion. In addition, a numerical experiment is performed using the three-current model to illustrate the application of the pacing protocol and the evaluation of the criterion.}, Doi = {10.1103/physreve.67.031904}, Key = {fds246493} } @article{fds246316, Author = {Kul'minskii, A and Gauthier, DJ and Vilaseca, R and Fernandez-Soler, JJ and Font, JL}, Title = {Polarization dynamics of two-photon and cascade lasers in the presence of an arbitrarily directed magnetic field}, Journal = {Journal of Optics B: Quantum and Semiclassical Optics}, Volume = {5}, Number = {3}, Pages = {243-253}, Publisher = {IOP Publishing}, Year = {2003}, Month = {June}, url = {http://dx.doi.org/10.1088/1464-4266/5/3/308}, Abstract = {We study theoretically the polarization dynamics of a new type of quantum oscillator that is based on the two-photon stimulated emission process in the presence of a magnetic field of arbitrary orientation. Both cases of cascade (small intermediate-state atomic detuning) and two-photon (large atomic detuning) lasers are considered. The primary goal of this work is to investigate the origin of recently observed polarization instabilities in a two-photon laser (Pfister et al 2001 Phys. Rev. Lett. 86 4512) using a highly simplified model. It is found that the two-photon laser can emit linearly polarized radiation with its plane of polarization orthogonal to the direction of the magnetic field at small magnetic field strengths. It can also emit elliptically polarized radiation over a large range of magnetic field strengths and orientations. When the magnetic field deviates from a direction perpendicular to the laser cavity axis periodic instabilities can appear through a Hopf bifurcation. This dynamic regime could have contributed to the polarization instabilities observed in the experiment.}, Doi = {10.1088/1464-4266/5/3/308}, Key = {fds246316} } @article{fds246467, Author = {Gauthier, DJ}, Title = {Resource letter: CC-1: Controlling chaos}, Journal = {American Journal of Physics}, Volume = {71}, Number = {8}, Pages = {750-759}, Publisher = {American Association of Physics Teachers (AAPT)}, Year = {2003}, Month = {August}, ISSN = {0002-9505}, url = {http://dx.doi.org/10.1119/1.1572488}, Abstract = {This Resource Letter provides a guide to the literature on controlling chaos. Journal articles, books, and web pages are provided for the following: controlling chaos, controlling chaos with weak periodic perturbations, controlling chaos in electronic circuits, controlling spatiotemporal chaos, targeting trajectories of nonlinear dynamical systems, synchronizing chaos, communicating with chaos, applications of chaos control in physical systems, and applications of chaos control in biological systems. © 2003 American Association of Physics Teachers.}, Doi = {10.1119/1.1572488}, Key = {fds246467} } @article{fds304566, Author = {Stenner, MD and Gauthier, DJ and Neifeld, MA}, Title = {The speed of information in a 'fast-light' optical medium.}, Journal = {Nature}, Volume = {425}, Number = {6959}, Pages = {695-698}, Year = {2003}, Month = {October}, url = {http://www.ncbi.nlm.nih.gov/pubmed/14562097}, Abstract = {One consequence of the special theory of relativity is that no signal can cause an effect outside the source light cone, the space-time surface on which light rays emanate from the source. Violation of this principle of relativistic causality leads to paradoxes, such as that of an effect preceding its cause. Recent experiments on optical pulse propagation in so-called 'fast-light' media--which are characterized by a wave group velocity upsilon(g) exceeding the vacuum speed of light c or taking on negative values--have led to renewed debate about the definition of the information velocity upsilon(i). One view is that upsilon(i) = upsilon(g) (ref. 4), which would violate causality, while another is that upsilon(i) = c in all situations, which would preserve causality. Here we find that the time to detect information propagating through a fast-light medium is slightly longer than the time required to detect the same information travelling through a vacuum, even though upsilon(g) in the medium vastly exceeds c. Our observations are therefore consistent with relativistic causality and help to resolve the controversies surrounding superluminal pulse propagation.}, Doi = {10.1038/nature02016}, Key = {fds304566} } @article{fds246369, Author = {Stenner, MD and Gauthier, DJ}, Title = {Observation of large "fast light" pulse advancement without distortion}, Volume = {89}, Pages = {QMK3/1-QMK3/2}, Year = {2003}, Month = {December}, Abstract = {We observe pulses advanced by 15% of their width and experiencing only minor distortion using laser-driven potassium atoms in a novel configuration that avoids competing nonlinear optical effects. ©2002 Optical Society of America.}, Key = {fds246369} } @article{fds304563, Author = {Tolkacheva, EG and Romeo, MM and Guerraty, M and Gauthier, DJ}, Title = {Condition for alternans and its control in a two-dimensional mapping model of paced cardiac dynamics}, Journal = {Physical Review E Statistical, Nonlinear, and Soft Matter Physics}, Volume = {69}, Number = {3 1}, Pages = {031904}, Year = {2004}, Month = {March}, ISSN = {1539-3755}, url = {http://dx.doi.org/10.1103/PhysRevE.69.031904}, Abstract = {A two-dimensional mapping model of a paced, isolated cardiac cell, which relates the duration of the action potential to the two preceding diastolic intervals as well as the preceding action potential duration, was studied. The model that was used displayed a rate-dependent restitution and memory. A control was initiated by carrying forward small adjustments to the pacing interval in order to suppress the alternans and stabilize the 1:1 response pattern displayed by the model. The gain that is necessary to establish control was shown to vary siginificantly depending on the value of the slope of the standard restitution curve.}, Doi = {10.1103/PhysRevE.69.031904}, Key = {fds304563} } @article{fds246500, Author = {Blakely, JN and Illing, L and Gauthier, DJ}, Title = {High-Speed Chaos in an Optical Feedback System With Flexible Timescales}, Journal = {Ieee Journal of Quantum Electronics}, Volume = {40}, Number = {3}, Pages = {299-305}, Publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, Year = {2004}, Month = {March}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/IEEEjqe40_299.pdf}, Abstract = {We describe a new optoelectronic device with time-delayed feedback that uses a Mach-Zehnder interferometer as passive nonlinearity and a semiconductor laser as a current-to-optical-frequency converter. Band-limited feedback allows tuning of the characteristic time scales of both the periodic and high dimensional chaotic oscillations that can be generated with the device. Our implementation of the device produces oscillations in the frequency range of tens to hundreds of megahertz. We develop a model and use it to explore the experimentally observed Andronov-Hopf bifurcation of the steady state and to estimate the dimension of the chaotic attractor.}, Doi = {10.1109/JQE.2003.823021}, Key = {fds246500} } @article{fds246441, Author = {Tolkacheva, EG and Romeo, MM and Guerraty, M and Gauthier, DJ}, Title = {Condition for alternans and its control in a two-dimensional mapping model of paced cardiac dynamics.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {69}, Number = {3 Pt 1}, Pages = {031904}, Year = {2004}, Month = {March}, ISSN = {1539-3755}, url = {http://www.ncbi.nlm.nih.gov/pubmed/15089319}, Abstract = {We investigate a two-dimensional mapping model of a paced, isolated cardiac cell that relates the duration of the action potential to the two preceding diastolic intervals as well as the preceding action potential duration. The model displays rate-dependent restitution and hence memory. We derive a criterion for the stability of the 1:1 response pattern displayed by the model. This criterion can be written in terms of experimentally measured quantities-the slopes of restitution curves obtained via different pacing protocols. In addition, we analyze the two-dimensional mapping model in the presence of closed-loop feedback control. The control is initiated by making small adjustments to the pacing interval in order to suppress alternans and stabilize the 1:1 pattern. We find that the domain of control does not depend on the functional form of the map, and, in the general case, is characterized by a combination of the slopes. We show that the gain gamma necessary to establish control may vary significantly depending on the value of the slope of the so-called standard restitution curve (herein denoted as S12), but that the product gammaS12 stays approximately in the same range.}, Doi = {10.1103/physreve.69.031904}, Key = {fds246441} } @article{fds246440, Author = {Stenner, MD and Gauthier, DJ and Neifeld, MA}, Title = {Superluminal speed of information? (reply)}, Journal = {Nature}, Volume = {429}, Number = {6987}, Pages = {40-40}, Publisher = {Springer Nature}, Year = {2004}, Month = {May}, ISSN = {0028-0836}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000221222100036&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Doi = {10.1038/nature02587}, Key = {fds246440} } @article{fds246499, Author = {Blakely, JN and Illing, L and Gauthier, DJ}, Title = {Controlling fast chaos in delay dynamical systems.}, Journal = {Physical Review Letters}, Volume = {92}, Number = {19}, Pages = {193901}, Year = {2004}, Month = {May}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/15169402}, Abstract = {We introduce a novel approach for controlling fast chaos in time-delay dynamical systems and use it to control a chaotic photonic device with a characteristic time scale of approximately 12 ns. Our approach is a prescription for how to implement existing chaos-control algorithms in a way that exploits the system's inherent time delay and allows control even in the presence of substantial control-loop latency (the finite time it takes signals to propagate through the components in the controller). This research paves the way for applications exploiting fast control of chaos, such as chaos-based communication schemes and stabilizing the behavior of ultrafast lasers.}, Doi = {10.1103/physrevlett.92.193901}, Key = {fds246499} } @article{fds246498, Author = {Kalb, SS and Dobrovolny, HM and Tolkacheva, EG and Idriss, SF and Krassowska, W and Gauthier, DJ}, Title = {The restitution portrait: a new method for investigating rate-dependent restitution.}, Journal = {Journal of Cardiovascular Electrophysiology}, Volume = {15}, Number = {6}, Pages = {698-709}, Year = {2004}, Month = {June}, ISSN = {1045-3873}, url = {http://www.ncbi.nlm.nih.gov/pubmed/15175067}, Abstract = {INTRODUCTION: Electrical restitution, relating action potential duration (APD) to diastolic interval (DI), was believed to determine the stability of heart rhythm. However, recent studies demonstrate that stability also depends on long-term APD changes caused by memory. This study presents a new method for investigation of rate- and memory-dependent aspects of restitution and for assessment of mapping models of APD. METHODS AND RESULTS: Bullfrog ventricular myocardium was paced with a "perturbed downsweep protocol." Starting from a basic cycle length (BCL) of 1,000 ms, the tissue was paced until steady state was achieved, followed by single beats of longer and shorter cycle lengths. BCL was decreased by 50 to 100 ms and the process repeated. All APDs were plotted as a function of the preceding DI, which allowed simultaneous observation of dynamic, S1-S2, and two constant-BCL restitution curves in a "restitution portrait." Responses were classified as 1:1 (stimulus:response), transient 2:2, or persistent 2:2 (alternans) and were related to the slopes of the restitution curves. None of these slopes approached unity for the persistent 2:2 response, demonstrating that the traditional restitution condition does not predict alternans. The restitution portrait was used to evaluate three mapping models of APD. The models with no memory and with one-beat memory did not produce restitution portraits similar to the experimental one. A model with two-beat memory produced a qualitatively similar portrait. CONCLUSION: The restitution portrait allows a more comprehensive assessment of cardiac dynamics than methods used to date. Further study of models with memory may result in a clinical criterion for electrical instability.}, Doi = {10.1046/j.1540-8167.2004.03550.x}, Key = {fds246498} } @article{fds246501, Author = {Tolkacheva, EG and Romeo, MM and Gauthier, DJ}, Title = {Control of cardiac alternans in a mapping model with memory}, Journal = {Physica D: Nonlinear Phenomena}, Volume = {194}, Number = {3-4}, Pages = {385-391}, Publisher = {Elsevier BV}, Year = {2004}, Month = {July}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PhysicaD194_385.pdf}, Abstract = {A generic feature of cardiac muscle is that the duration of an action potential depends on the long-term history of previous action potentials, known as cardiac 'memory'. Even though memory is known to be an important physiological response, there have only been limited studies of its effect on cardiac dynamics. Here, we investigate a map-based model of paced myocardium in the presence of closed-loop feedback control. The model relates the duration of an action potential to the preceding diastolic interval as well as the preceding action potential duration and thus has some degree of memory. We find that the range of parameters over which control is effective can be enlarged or reduced by memory, a prediction that is independent of the specific functional form of the map. Our work suggests that modifying the degree of memory (e.g., pharmacological agents) with some form of feedback control may be an effective strategy for the maintenance of normal cardiac function. © 2004 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.physd.2004.03.008}, Key = {fds246501} } @article{fds246497, Author = {Cain, JW and Tolkacheva, EG and Schaeffer, DG and Gauthier, DJ}, Title = {Rate-dependent propagation of cardiac action potentials in a one-dimensional fiber.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {70}, Number = {6 Pt 1}, Pages = {061906}, Year = {2004}, Month = {December}, ISSN = {1539-3755}, url = {http://www.ncbi.nlm.nih.gov/pubmed/15697401}, Abstract = {Action potential duration (APD) restitution, which relates APD to the preceding diastolic interval (DI), is a useful tool for predicting the onset of abnormal cardiac rhythms. However, it is known that different pacing protocols lead to different APD restitution curves (RCs). This phenomenon, known as APD rate dependence, is a consequence of memory in the tissue. In addition to APD restitution, conduction velocity restitution also plays an important role in the spatiotemporal dynamics of cardiac tissue. We present results concerning rate-dependent restitution in the velocity of propagating action potentials in a one-dimensional fiber. Our numerical simulations show that, independent of the amount of memory in the tissue, the wave-back velocity exhibits pronounced rate dependence and the wave-front velocity does not. Moreover, the discrepancy between wave-back velocity RCs is most significant for a small DI. We provide an analytical explanation of these results, using a system of coupled maps to relate the wave-front and wave-back velocities. Our calculations show that rate-dependent wave-back velocity can be present even if neither APD nor wave-front velocity exhibits rate dependence.}, Doi = {10.1103/physreve.70.061906}, Key = {fds246497} } @article{fds340696, Author = {Jeong, H and Dawes, AM and Gauthier, DJ}, Title = {Direct observation of optical precursors in a region of anomalous dispersion}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Abstract = {We observe the creation of optical precursors when a step-modulated optical pulse propagates through a linear resonant absorber. The precursors are the dominant part of the transmitted field, displaying 100% transmission at their maximum amplitude. © 2005 Optical Society of America.}, Key = {fds340696} } @article{fds44142, Author = {L. Illing and D.J. Gauthier}, Title = {Hopf bifurcations in time-delay systems with band-limited feedback}, Journal = {Physica D: Nonlinear Phenomena}, Volume = {210}, Pages = {180}, Year = {2005}, url = {http://arxiv.org/abs/nlin/0507040}, Key = {fds44142} } @article{fds52845, Author = {L. Illing and J. N. Blakely and D. Gauthier}, Title = {Time delay systems with band-limited feedback}, Pages = {1115-1123}, Booktitle = {proceedings of the Fifth EUROMECH Nonlinear Dynamics Conference (ENOC-2005), Eindhoven, The Netherlands, August 7--12}, Editor = {D.H. Van Campen and M.D. Lazurko W.P.J.M. Van Der Oever}, Year = {2005}, Key = {fds52845} } @article{fds246225, Author = {Gaeta, AL and Okawachi, Y and Ghosh, S and Sharping, JE and Bigelow, MS and Schweinsberg, A and Boyd, RW and Zhu, Z and Gauthier, DJ}, Title = {Optically tunable “slow“ light in waveguides}, Journal = {Nonlinear Guided Waves and Their Applications, Nlgw 2005}, Year = {2005}, Month = {January}, ISBN = {1557527911}, Abstract = {We describe our recent research efforts to produce tunable, all-optical slow light by stimulated scattering in conventional optical fibers and via electromagnetically-induced transparency in photonic band-gap fibers. © 2005 Optical Society of America.}, Key = {fds246225} } @article{fds246237, Author = {Gaeta, AL and Okawachi, Y and Ghosh, S and Sharping, JE and Bigelow, MS and Schweinsberg, A and Boyd, RW and Zhu, Z and Gauthier, DJ}, Title = {Optically tunable "slow" light in waveguides}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Month = {January}, Abstract = {We describe our recent research efforts to produce tunable, all-optical slow light by stimulated scattering in conventional optical fibers and via electromagnetically-induced transparency in photonic band-gap fibers. © 2005 Optical Society of America.}, Key = {fds246237} } @article{fds246242, Author = {Zhu, Z and Gauthier, DJ and Okawachi, Y and Gaeta, AL and Schweinsberg, A and Boyd, RW}, Title = {Numerical study of slow light via stimulated brillouin scattering in optical fibers}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Month = {January}, Abstract = {We study numerically Stokes pulse propagation in a continuous-wave-pumped Brillouin fiber amplifier. Time delay and pulse broadening of the Stokes pulse are studied in the small-signal and saturation regimes. © 2005 Optical Society of America.}, Key = {fds246242} } @article{fds246243, Author = {Jeong, H and Dawes, AMC and Gauthier, DJ}, Title = {Observation of the sommerfeld precursor}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Month = {January}, Abstract = {We study the generation of optical precursors when a step-modulated optical pulse propagates through a linear resonant absorber. The Sommerfeld precursor is the dominant part of the transmitted field, and experiences essentially no absorption. © 2005 Optical Society of America.}, Key = {fds246243} } @article{fds246244, Author = {Gauthier, DJ}, Title = {Optical visualization of nonlinear pattern dynamics in biological systems}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Month = {January}, Abstract = {The development of voltage-sensitive and ion-specific organic dyes has revolutionized the visualization of complex spatio-temporal patterns in biological systems. I will review how these tools can be used to visual dynamics of the heart. © 2005 Optical Society of America.}, Key = {fds246244} } @article{fds246245, Author = {Zhu, Z and Gauthier, DJ and Okawachi, Y and Gaeta, AL and Schweinsberg, A and Boyd, RW}, Title = {Numerical study of slow light via stimulated Brillouin scattering in optical fibers}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Month = {January}, Abstract = {We study numerically Stokes pulse propagation in a continuous-wave-pumped Brillouin fiber amplifier. Time delay and pulse broadening of the Stokes pulse are studied in the small-signal and saturation regimes. © 2005 Optical Society of America.}, Key = {fds246245} } @article{fds246246, Author = {Boyd, RW and Gauthier, DJ and Gaeta, AL and Willner, AE}, Title = {Limits on the time delay induced by slow-light propagation}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Month = {January}, Abstract = {We show that there are no fundamental limits to the maximum time delay that can be achieved for pulses propagating through slow-light media, thus suggesting the importance of slowlight methods for practical applications. © 2005 Optical Society of America.}, Key = {fds246246} } @article{fds246325, Author = {Dawes, AMC and Illing, L and Clark, SM and Gauthier, DJ}, Title = {All-optical switch controls strong beams with weak ones}, Journal = {Optics and Photonics News}, Volume = {16}, Number = {12 SPEC. ISS.}, Pages = {34}, Publisher = {The Optical Society}, Year = {2005}, Month = {January}, ISSN = {1047-6938}, url = {http://dx.doi.org/10.1364/OPN.16.12.000034}, Abstract = {Switches that are capable of redirecting pulses of light are important components of high speed optical communication networks. These devices help an incoming switching beam to redirect other beams via light-by-light scattering. Another desirable property property of all optical switches is that the output beams are controlled by a weaker switch beam. current switches however tend to control a weak beams with a strong one.}, Doi = {10.1364/OPN.16.12.000034}, Key = {fds246325} } @article{fds246326, Author = {Okawachi, Y and Sharping, JE and Gaeta, AL and Bigelow, MS and Schweinsberg, A and Boyd, RW and Zhu, Z and Gauthier, DJ}, Title = {All-optical tunable slow-light delays via stimulated scattering}, Journal = {Optics and Photonics News}, Volume = {16}, Number = {12 SPEC. ISS.}, Pages = {42}, Publisher = {The Optical Society}, Year = {2005}, Month = {January}, ISSN = {1047-6938}, url = {http://dx.doi.org/10.1364/OPN.16.12.000042}, Abstract = {In systems operating at ultrahigh speeds, where information is encoded with pulses of light, optical devices that eliminate the need for optical/electronic conversion of the information should be used. A new type of optical pulse delay scheme based on stimulated scattering that represents an important advance in flexibility and performance is discussed. The use of stimulated scattering to produce tunable delays represents an important advance, given that off the shelf components can be used. The slow light resonance can be tuned to any wavelength, thus allowing for operation in the S-, C-, and L-band optical communication windows.}, Doi = {10.1364/OPN.16.12.000042}, Key = {fds246326} } @article{fds246443, Author = {Font, JL and Fernández-Soler, JJ and Vilaseca, R and Gauthier, DJ}, Title = {Multiphoton lasing in atomic potassium: Steady-state and dynamic behavior}, Journal = {Physical Review A}, Volume = {72}, Number = {6}, Pages = {063810}, Publisher = {American Physical Society (APS)}, Year = {2005}, Month = {January}, url = {http://dx.doi.org/10.1103/PhysRevA.72.063810}, Abstract = {We show theoretically that it is possible to generate laser light based on two-photon and other high-order multiphoton processes when an atomic beam of optically driven potassium atoms crosses a high-finesse optical cavity. We use a rigorous model that takes into account all the atomic substates involved in the optical interactions and is valid for any drive and lasing field intensities. The polarizations of the drive and lasing fields are assumed to be fixed. Stable and unstable laser emission branches are obtained, which are represented as a function of cavity detuning and are analyzed in terms of the fundamental quantum processes yielding them. Closed-curve laser-emission profiles are obtained for multiphoton lasing based on processes involving more than one lasing photon. Two-photon laser emission branches show relatively long segments of stationary emission, combined in general with some segments of nonstationary emission, or with segments of mixture with three-photon emission processes. Rayleigh and hyper-Rayleigh processes can become simultaneously resonant, entailing in such case a large and fast transfer of population from the atomic initial ground sublevel to other ground sublevels with different z components of the total angular momentum. They could be useful in generating multiphoton correlated field states. In all cases the largest laser emission intensities are obtained from the highest-order processes, rather than the lowest. These results open the way to the understanding of experiments performed in the past years and suggest possibilities for more efficient and varied types of multiphoton laser operation. © 2005 The American Physical Society.}, Doi = {10.1103/PhysRevA.72.063810}, Key = {fds246443} } @article{fds246444, Author = {Gauthier, D}, Title = {Slow light brings faster communications}, Journal = {Physics World}, Volume = {18}, Number = {12}, Pages = {30-32}, Publisher = {IOP Publishing}, Year = {2005}, Month = {January}, ISSN = {0953-8585}, url = {http://dx.doi.org/10.1088/2058-7058/18/12/31}, Abstract = {Researchers have significantly managed to reduce the speed of light in an optical fibre, which could open the door to all-optical routers for telecommunication. Routers switch pulses of light from one fibre to another, ending up at the correct destination. Now they are converting optical into electrical pulses, perform the switching operation and then convert the electrical signals back into the optical pulse. The main difficulty in designing a all-optical router is to find a way to temporarily store or buffer the packets of information. A optical data regenerator device uses slow light to create a stream of optical data pulses that will be distorted after traveling a long distance along an optical fibre.}, Doi = {10.1088/2058-7058/18/12/31}, Key = {fds246444} } @article{fds246446, Author = {Zhu, Z and Gauthier, DJ and Okawachi, Y and Sharping, JE and Gaeta, AL and Boyd, RW and Willner, AE}, Title = {Numerical study of all-optical slow-light delays via stimulated Brillouin scattering in an optical fiber}, Journal = {Journal of the Optical Society of America B}, Volume = {22}, Number = {11}, Pages = {2378-2384}, Publisher = {The Optical Society}, Year = {2005}, Month = {January}, ISSN = {0740-3224}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/JOSAB22_2378.pdf}, Abstract = {We study numerically all-optical slow-light delays in room-temperature single-mode optical fibers induced by stimulated Brillouin scattering. We consider the propagation of a pulse through a cw-pumped Brillouin fiber amplifier, where the carrier frequency of the pulse is tuned near the Stokes resonance. Pulse delay and broadening of the Stokes pulse are studied in the small-signal and gain-saturation regimes. Pulse delay is shown to be limited by saturation of the Brillouin amplifier. In the small-signal regime, both time delay and pulse broadening increase with increasing gain. In the gain-saturation regime, both time delay and broadening decrease with increasing gain, and the pulse even achieves advancement. Time delay of more than one pulse-width is observed with modest pulse distortion, and over one pulse-width advancement can be obtained with larger pulse distortion in the gain-saturation regime. © 2005 Optical Society of America.}, Doi = {10.1364/JOSAB.22.002378}, Key = {fds246446} } @article{fds311316, Author = {Okawachi, Y and Sharping, JE and Gaeta, AL and Bigelow, MS and Schweinsberg, A and Boyd, RW and Zhu, Z and Gauthier, DJ}, Title = {Tunable all-optical delays via brillouin slow light in an optical fiber}, Journal = {Optics Infobase Conference Papers}, Year = {2005}, Month = {January}, Abstract = {We demonstrate a technique for generating tunable all-optical delays as long as 20 ns in single-mode fibers at telecommunication wavelengths using stimulated Brillouin scattering. This process represents a step towards implementing slow-light in telecommunication systems. © 2005 Optical Society of America.}, Key = {fds311316} } @article{fds311267, Author = {Jeong, H and Dawes, AM and Gauthier, DJ}, Title = {Direct observation of optical precursors in a region of anomalous dispersion}, Journal = {Optics Infobase Conference Papers}, Volume = {1}, Pages = {241-243}, Year = {2005}, Month = {January}, ISSN = {2162-2701}, Abstract = {We observe the creation of optical precursors when a step-modulated optical pulse propagates through a linear resonant absorber. The precursors are the dominant part of the transmitted field, displaying 100% transmission at their maximum amplitude. © 2005 Optical Society of America.}, Key = {fds311267} } @article{fds246394, Author = {Boyd, RW and Gauthier, DJ and Gaeta, AL and Willner, AE}, Title = {Maximum time delay achievable on propagation through a slow-light medium}, Journal = {Physical Review A}, Volume = {71}, Number = {2}, Pages = {023801}, Publisher = {American Physical Society (APS)}, Year = {2005}, Month = {February}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRA71023801.pdf}, Abstract = {We consider the question of whether there are any fundamental limits to the maximum time delay that can be achieved for a pulse propagating through a slow-light medium. We include in our analysis what we consider to be the dominant competing effects, and we show that in principle they do not lead to a limitation on the maximum achievable time delay. From this result we conclude that, through optimization, one should be able to delay a pulse by very many pulse lengths; the ability to do so can have important implications for the use of slow-light methods for applications in photonics. © 2005 The American Physical Society.}, Doi = {10.1103/PhysRevA.71.023801}, Key = {fds246394} } @article{fds246431, Author = {Stenner, MD and Gauthier, DJ and Neifeld, MA}, Title = {Fast causal information transmission in a medium with a slow group velocity.}, Journal = {Physical Review Letters}, Volume = {94}, Number = {5}, Pages = {053902}, Year = {2005}, Month = {Spring}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/15783642}, Abstract = {It is widely believed that the velocity of information upsiloni encoded on an optical pulse is equal to the group velocity upsilong, at least when upsilong is less than the speed of light in vacuum c. On the other hand, several authors suggest that upsiloni=c, although the size of the signal traveling at this velocity may be small, thereby making it difficult to measure. Here, we measure upsiloni for pulses propagating through a resonant "slow-light" medium where upsilong approximately 0.006c. We find upsiloni=1.03c(+0.49c)-0.25c, or that upsiloni approximately 168upsilong, clearly demonstrating that the speed of information cannot be generally described by upsilong, but is characterized by its own velocity.}, Doi = {10.1103/physrevlett.94.053902}, Key = {fds246431} } @article{fds246437, Author = {Dawes, AMC and Illing, L and Clark, SM and Gauthier, DJ}, Title = {All-optical switching in rubidium vapor.}, Journal = {Science (New York, N.Y.)}, Volume = {308}, Number = {5722}, Pages = {672-674}, Year = {2005}, Month = {April}, url = {http://www.ncbi.nlm.nih.gov/pubmed/15860622}, Abstract = {We report on an all-optical switch that operates at low light levels. It consists of laser beams counterpropagating through a warm rubidium vapor that induce an off-axis optical pattern. A switching laser beam causes this pattern to rotate even when the power in the switching beam is much lower than the power in the pattern. The observed switching energy density is very low, suggesting that the switch might operate at the single-photon level with system optimization. This approach opens the possibility of realizing a single-photon switch for quantum information networks and for improving transparent optical telecommunication networks.}, Doi = {10.1126/science.1110151}, Key = {fds246437} } @article{fds246460, Author = {Okawachi, Y and Bigelow, MS and Sharping, JE and Zhu, Z and Schweinsberg, A and Gauthier, DJ and Boyd, RW and Gaeta, AL}, Title = {Tunable all-optical delays via Brillouin slow light in an optical fiber.}, Journal = {Physical Review Letters}, Volume = {94}, Number = {15}, Pages = {153902}, Year = {2005}, Month = {April}, ISSN = {0031-9007}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRL94_153902.pdf}, Abstract = {We demonstrate a technique for generating tunable all-optical delays in room temperature single-mode optical fibers at telecommunication wavelengths using the stimulated Brillouin scattering process. This technique makes use of the rapid variation of the refractive index that occurs in the vicinity of the Brillouin gain feature. The wavelength at which the induced delay occurs is broadly tunable by controlling the wavelength of the laser pumping the process, and the magnitude of the delay can be tuned continuously by as much as 25 ns by adjusting the intensity of the pump field. The technique can be applied to pulses as short as 15 ns. This scheme represents an important first step towards implementing slow-light techniques for various applications including buffering in telecommunication systems.}, Doi = {10.1103/physrevlett.94.153902}, Key = {fds246460} } @article{fds311268, Author = {Okawachi, Y and Bigelow, MS and Sharping, JE and Zhu, Z and Schweinsberg, A and Gauthier, DJ and Boyd, RW and Gaeta, AL}, Title = {Tunable all-optical delays via brillouin slow light in an optical fiber}, Journal = {Physical Review Letters}, Volume = {94}, Number = {15}, Pages = {511-513}, Year = {2005}, Month = {April}, url = {http://dx.doi.org/10.1103/PhysRevLett.94.153902}, Abstract = {We demonstrate a technique for generating tunable all-optical delays in room temperature single-mode optical fibers at telecommunication wavelengths using the stimulated Brillouin scattering process. This technique makes use of the rapid variation of the refractive index that occurs in the vicinity of the Brillouin gain feature. The wavelength at which the induced delay occurs is broadly tunable by controlling the wavelength of the laser pumping the process, and the magnitude of the delay can be tuned continuously by as much as 25 ns by adjusting the intensity of the pump field. The technique can be applied to pulses as short as 15 ns. This scheme represents an important first step towards implementing slow-light techniques for various applications including buffering in telecommunication systems. © 2005 The American Physical Society.}, Doi = {10.1103/PhysRevLett.94.153902}, Key = {fds311268} } @article{fds246471, Author = {Kalb, SS and Tolkacheva, EG and Schaeffer, DG and Gauthier, DJ and Krassowska, W}, Title = {Restitution in mapping models with an arbitrary amount of memory.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {15}, Number = {2}, Pages = {23701}, Year = {2005}, Month = {June}, ISSN = {1054-1500}, url = {http://www.ncbi.nlm.nih.gov/pubmed/16035891}, Abstract = {Restitution, the characteristic shortening of action potential duration (APD) with increased heart rate, has been studied extensively because of its purported link to the onset of fibrillation. Restitution is often represented in the form of mapping models where APD is a function of previous diastolic intervals (DIs) and/or APDs, A(n+1)=F(D(n),A(n),D(n-1),A(n-1),...), where A(n+1) is the APD following a DI given by D(n). The number of variables previous to D(n) determines the degree of memory in the mapping model. Recent experiments have shown that mapping models should contain at least three variables (D(n),A(n),D(n-1)) to reproduce a restitution portrait (RP) that is qualitatively similar to that seen experimentally, where the RP shows three different types of restitution curves (RCs) [dynamic, S1-S2, and constant-basic cycle length (BCL)] simultaneously. However, an interpretation of the different RCs has only been presented in detail for mapping models of one and two variables. Here we present an analysis of the different RCs in the RP for mapping models with an arbitrary amount of memory. We determine the number of variables necessary to represent the different RCs in the RP. We also present a graphical visualization of these RCs. Our analysis reveals that the dynamic and S1-S2 RCs reside on two-dimensional surfaces, and therefore provide limited information for mapping models with more than two variables. However, constant-BCL restitution is a feature of the RP that depends on higher dimensions and can possibly be used to determine a lower bound on the dimensionality of cardiac dynamics.}, Doi = {10.1063/1.1876912}, Key = {fds246471} } @article{fds246319, Author = {Dawes, AMC and Clark, SM and Illing, L and Gauthier, DJ}, Title = {Observation of ultra-low-light-level all-optical switching}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {5735}, Pages = {60-68}, Booktitle = {Proc. SPIE}, Publisher = {SPIE}, Editor = {H. J. Coufal and Z. U. Hasan and A. E. Craig}, Year = {2005}, Month = {August}, ISSN = {0277-786X}, url = {http://dx.doi.org/10.1117/12.601704}, Abstract = {Photonic circuits require elements that can control optical signals with other optical signals. Ultra-low-light-level operation of all-optical switches opens the possibility of photonic devices that operate in the single-quantum regime, a prerequisite for quantum-photonic devices. We describe a new type of all-optical switch that exploits the extreme sensitivity to small perturbations displayed by instability-generated dissipative optical patterns. Such patterns, when controlled by applied perturbations, enable control of microwatt-power-level output beams by an input beam that is over 600 times weaker. In comparison, essentially all experimental realizations of light-by-light switching have been limited to controlling weak beams with beams of either comparable or higher power, thus limiting their implementation in cascaded switching networks or computation machines. Furthermore, current research suggests that the energy density required to actuate an all-optical switch is of the order of one photon per optical cross section. Our measured switching energy density of ∼4.4 × 10-2 photons per cross section suggests that our device can operate at the single-photon level with modest system improvement.}, Doi = {10.1117/12.601704}, Key = {fds246319} } @article{fds246470, Author = {Illing, L and Gauthier, DJ}, Title = {Hopf bifurcations in time-delay systems with band-limited feedback}, Journal = {Physica D: Nonlinear Phenomena}, Volume = {210}, Number = {3-4}, Pages = {180-202}, Publisher = {Elsevier BV}, Year = {2005}, Month = {October}, url = {http://dx.doi.org/10.1016/j.physd.2005.07.008}, Abstract = {We investigate the steady-state solution and its bifurcations in time-delay systems with band-limited feedback. This is a first step in a rigorous study concerning the effects of AC-coupled components in nonlinear devices with time-delayed feedback. We show that the steady state is globally stable for small feedback gain and that local stability is lost, generically, through a Hopf bifurcation for larger feedback gain. We provide simple criteria that determine whether the Hopf bifurcation is supercritical or subcritical based on the knowledge of the first three terms in the Taylor-expansion of the nonlinearity. Furthermore, the presence of double-Hopf bifurcations of the steady state is shown, which indicates possible quasiperiodic and chaotic dynamics in these systems. As a result of this investigation, we find that AC-coupling introduces fundamental differences to systems of Ikeda-type [K. Ikeda, K. Matsumoto, High-dimensional chaotic behavior in systems with time-delayed feedback, Physica D 29 (1987) 223-235] already at the level of steady-state bifurcations, e.g. bifurcations exist in which limit cycles are created with periods other than the fundamental "period-2" mode found in Ikeda-type systems. © 2005 Elsevier B.V. All rights reserved.}, Doi = {10.1016/j.physd.2005.07.008}, Key = {fds246470} } @article{fds246321, Author = {Zhu, Z and Gauthier, DJ and Okawachi, Y and Gaeta, AL and Schweinsberg, A and Boyd, RW}, Title = {Numerical study of slow light via stimulated Brillouin scattering in optical fibers}, Journal = {Quantum Electronics and Laser Science Conference (Qels)}, Volume = {2}, Pages = {844-846}, Year = {2005}, Month = {October}, Abstract = {We study numerically Stokes pulse propagation in a continuous-wave-pumped Brillouin fiber amplifier. Time delay and pulse broadening of the Stokes pulse are studied in the small-signal and saturation regimes. ©2005 Optical Society of America.}, Key = {fds246321} } @article{fds246370, Author = {Boyd, RW and Gauthier, DJ and Gaeta, AL and Willner, AE}, Title = {Limits on the time delay induced by slow-light propagation}, Journal = {Quantum Electronics and Laser Science Conference (Qels)}, Volume = {1}, Pages = {214-216}, Year = {2005}, Month = {October}, Abstract = {We show that there are no fundamental limits to the maximum time delay that can be achieved for pulses propagating through slow-light media, thus suggesting the importance of slow-light methods for practical applications. © 2005 Optical Society of America.}, Key = {fds246370} } @article{fds246324, Author = {Boyd, RW and Gauthier, DJ and Gaeta, AL and Willner, AE}, Title = {Erratum: Maximum time delay achievable on propagation through a slow-light medium (Physical Review A - Atomic, Molecular, and Optical Physics (2005) 71 (023801))}, Journal = {Physical Review A}, Volume = {72}, Number = {5}, Publisher = {American Physical Society (APS)}, Year = {2005}, Month = {November}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.72.059903}, Doi = {10.1103/PhysRevA.72.059903}, Key = {fds246324} } @article{fds246445, Author = {Stenner, MD and Neifeld, MA and Zhu, Z and Dawes, AMC and Gauthier, DJ}, Title = {Distortion management in slow-light pulse delay.}, Journal = {Optics Express}, Volume = {13}, Number = {25}, Pages = {9995-10002}, Year = {2005}, Month = {December}, ISSN = {1094-4087}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptExp13_9995.pdf}, Abstract = {We describe a methodology to maximize slow-light pulse delay subject to a constraint on the allowable pulse distortion. We show that optimizing over a larger number of physical variables can increase the distortion-constrained delay. We demonstrate these concepts by comparing the optimum slow-light pulse delay achievable using a single Lorentzian gain line with that achievable using a pair of closely-spaced gain lines. We predict that distortion management using a gain doublet can provide approximately a factor of 2 increase in slow-light pulse delay as compared with the optimum single-line delay. Experimental results employing Brillouin gain in optical fiber confirm our theoretical predictions.}, Doi = {10.1364/opex.13.009995}, Key = {fds246445} } @article{fds246434, Author = {Boyd, RW and Gauthier, DJ}, Title = {Transparency on an optical chip}, Journal = {An Invited Article in Nature}, Volume = {441}, Pages = {701}, Year = {2006}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/Nature441_701.pdf}, Key = {fds246434} } @article{fds246435, Author = {Boyd, RW and Gauthier, DJ and Gaeta, AL}, Title = {Applications of slow light in telecommunications}, Journal = {An Invited Article in Optics and Photonics News}, Volume = {7}, Number = {4}, Pages = {18}, Year = {2006}, ISSN = {1047-6938}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OPN_slow_light.pdf}, Abstract = {Slow-light techniques hold great promise for application in many areas of modern photonics, including telecommunications. Good progress is being made in the development of new techniques for producing controllable time delays in optical waveguides based on slow-light methods. The proposed applications of slow light are for the progress of optical buffering. Numerical modeling shows that the performance of a switching network under high traffic conditions can be dramatically increased through the use of such buffering. The key parameter of interest for a slow-light delay line is normalized time delay. A key issue in all slow-light experiments is finding the maximum modulation bandwidth that can experience the full slow-light effect.}, Key = {fds246435} } @article{fds246248, Author = {Shi, Z and Boyd, RW and Gauthier, DJ}, Title = {Spectroscopic interferometry using slow-light media}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {We consider a Mach-Zehnder interferometer with a slow-light medium in one of its arms. We show that the frequency/wavelength sensitivity is enhanced enormously because of the large difference in group indices between the two arms. © 2006 Optical Society of America.}, Key = {fds246248} } @article{fds246249, Author = {Zhu, Z and Gauthier, DJ}, Title = {XPM-induced pulse delay and advancement in optical fiber}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {Cross-phase-modulation-induced pulse delay or advancement in an optical fiber is analyzed. It is shown that XPM and group-velocity mismatch can lead to controllable pulse delay or advancement with negligible frequency shift. © 2005 Optical Society of America.}, Key = {fds246249} } @article{fds246251, Author = {Zhu, Z and Dawes, AMC and Gauthier, DJ and Stenner, MD and Neifeld, MA and Luo, T and Yu, C and Zhang, L and Willner, AE}, Title = {Recent advances in stimulated brillouin scattering slow light}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {We will discuss progress in achieving long, low-distortion and wide-bandwidth pulse delay via stimulated Brillouin scattering slow light. The technique works at telecommunication wavelength and uses off-the-shelf components. © 2006 Optical Society of America.}, Key = {fds246251} } @article{fds246252, Author = {Shi, Z and Boyd, RW and Zhu, Z and Gauthier, DJ and Pant, R and Stenner, MD and Neifeld, MA}, Title = {Distortion-reduced pulse-train propagation with large delay in a triple gain media}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {A slow light medium based on three closely spaced gain lines is studied. Both numerical calculations and experiments demonstrate that large delay can be achieved with large bandwidth and with very small distortion. © 2006 Optical Society of America.}, Key = {fds246252} } @article{fds246253, Author = {Zhu, Z and Gauthier, DJ and Okawachi, Y and Gaeta, AL and Schweinsberg, A and Boyd, RW}, Title = {Numerical study of slow light via stimulated Brillouin scattering in optical fibers}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {We study numerically Stokes pulse propagation in a continuous-wave-pumped Brillouin fiber amplifier. Time delay and pulse broadening of the Stokes pulse are studied in the small-signal and saturation regimes. © 2005 Optical Society of America.}, Key = {fds246253} } @article{fds246254, Author = {Gauthier, DJ and Zhu, Z and Dawes, AMC and Zhang, L and Willner, AE}, Title = {Optimizing broadband SBS slow light in an optical fiber}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {We describe how to optimize slow-light via stimulated Brillouin scattering in a room temperature optical fiber that is pumped with a spectrally broadened laser. Our recent experimental results on broadband SBS slow-light will be discussed. © 2006 Optical Society of America.}, Key = {fds246254} } @article{fds304567, Author = {Boyd, RW and Gauthier, DJ and Gaeta, AL}, Title = {Applications of slow light in telecommunications}, Journal = {Optics and Photonics News}, Volume = {17}, Number = {4}, Pages = {19-23}, Year = {2006}, Month = {January}, ISSN = {1047-6938}, Abstract = {Slow-light techniques hold great promise for application in many areas of modern photonics, including telecommunications. Good progress is being made in the development of new techniques for producing controllable time delays in optical waveguides based on slow-light methods. The proposed applications of slow light are for the progress of optical buffering. Numerical modeling shows that the performance of a switching network under high traffic conditions can be dramatically increased through the use of such buffering. The key parameter of interest for a slow-light delay line is normalized time delay. A key issue in all slow-light experiments is finding the maximum modulation bandwidth that can experience the full slow-light effect.}, Key = {fds304567} } @article{fds311266, Author = {Okawachi, Y and Sharping, JE and Gaeta, AL and Bigelow, MS and Schweinsberg, A and Boyd, RW and Zhu, Z and Gauthier, DJ}, Title = {Tunable all-optical delays via brillouin slow light in an optical fiber}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {We demonstrate a technique for generating tunable all-optical delays as long as 20 ns in single-mode fibers at telecommunication wavelengths using stimulated Brillouin scattering. This process represents a step towards implementing slow-light in telecommunication systems. © 2005 Optical Society of America.}, Key = {fds311266} } @article{fds340906, Author = {Dey, TN and Agarwal, GS and Gauthier, DJ}, Title = {Competition between electromagnetically induced transparency and Raman processes}, Journal = {Optics Infobase Conference Papers}, Year = {2006}, Month = {January}, Abstract = {We discuss the competition between electromagnetically induced transparency and Raman processes in a Λ system due to the cross talk among optical transitions. We compare theory with recent experimental work of Harada et al. © 2006 Optical Society of America.}, Key = {fds340906} } @article{fds246439, Author = {Gauthier, DJ and Gaeta, AL and Boyd, RW}, Title = {Slow light: From basics to future prospects}, Journal = {Photonics Spectra}, Volume = {40}, Number = {3}, Pages = {44-50}, Year = {2006}, Month = {March}, ISSN = {0731-1230}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PhotonicsSpectraSlowLight2006.pdf}, Abstract = {Motivated by the need for optically controllable pulse delays for applications such as optical buffering, data synchronization, optical memory and signal processing, researchers sought to control the speed of a pulse light from its vacuum speed. A revolution in the field came when researchers at Stanford University in California realized that the slow-light effect can be preserved while the effects of absortion are simultaneously canceled using a coherent optical effect occurring in a gas of atoms that have three energy levels. Although this result was impressive, it indicated that slow light based on electromagnetically induced transparency requires that the material medium be a low-density atomic vapor or an impurity-doped solid maintained at low temperature. A recent experiment performed at the University of Rochester in New York established that slow light based on coherent population oscillations could be observed with the use of ruby. A more recent research targeted the development of materials with a much faster population recovery. For instance, researchers at the University of California, Berkeley, and Texas A&M UNiversity in College Station observed slow light with a modulation bandwidth as large as 2.8 GHz in a semicondictor laser amplifier. Controllable slow-light delays due to stimulated Brillouin scattering in conventional telecommunication fibers were realized independently by two teams, one from Spain and another from the US.}, Key = {fds246439} } @article{fds246436, Author = {Jeong, H and Dawes, AMC and Gauthier, DJ}, Title = {Direct observation of optical precursors in a region of anomalous dispersion.}, Journal = {Physical Review Letters}, Volume = {96}, Number = {14}, Pages = {143901}, Year = {2006}, Month = {April}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/16712074}, Abstract = {We create optical precursors by propagating a step-modulated optical pulse through a linear resonant dielectric absorber. The field emerging from the dielectric consists of a several-nanosecond-long spike with near 100% transmission, which decays to a constant value expected from Beer's law. This high-transmission spike might be useful for imaging applications requiring penetrating optical radiation. We compare our observations to two different theories, revealing that the spike consists of both the Sommerfeld and Brillouin precursors.}, Doi = {10.1103/physrevlett.96.143901}, Key = {fds246436} } @article{fds246332, Author = {Boyd, RW and Gauthier, DJ}, Title = {Photonics: transparency on an optical chip.}, Journal = {Nature}, Volume = {441}, Number = {7094}, Pages = {701-702}, Year = {2006}, Month = {June}, ISSN = {0028-0836}, url = {http://dx.doi.org/10.1038/441701a}, Doi = {10.1038/441701a}, Key = {fds246332} } @article{fds246433, Author = {Zhu, Z and Gauthier, DJ}, Title = {Nearly transparent SBS slow light in an optical fiber.}, Journal = {Optics Express}, Volume = {14}, Number = {16}, Pages = {7238-7245}, Year = {2006}, Month = {August}, url = {http://www.ncbi.nlm.nih.gov/pubmed/19529093}, Abstract = {Slow-light delay via stimulated Brillouin scattering (SBS) in optical fibers is usually achieved with delay-dependent amplification that degrades system performance. To address this problem, we propose a SBS slow-light method that makes use of two widely separated anti-Stokes absorption resonances, and achieve nearly transparent slow light in an optical fiber. We demonstrate the method in a highly nonlinear optical fiber, and achieve a slow-light bandwidth of approximately 150 MHz and a relative of delay of approximately 0.3 for approximately 9-ns pulses with a signal attenuation of approximately 4.8 dB.}, Doi = {10.1364/oe.14.007238}, Key = {fds246433} } @article{fds246432, Author = {Illing, L and Gauthier, DJ}, Title = {Ultra-high-frequency chaos in a time-delay electronic device with band-limited feedback.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {16}, Number = {3}, Pages = {033119}, Year = {2006}, Month = {September}, ISSN = {1054-1500}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17014224}, Abstract = {We report an experimental study of ultra-high-frequency chaotic dynamics generated in a delay-dynamical electronic device. It consists of a transistor-based nonlinearity, commercially-available amplifiers, and a transmission-line for feedback. The feedback is band-limited, allowing tuning of the characteristic time-scales of both the periodic and high-dimensional chaotic oscillations that can be generated with the device. As an example, periodic oscillations ranging from 48 to 913 MHz are demonstrated. We develop a model and use it to compare the experimentally observed Hopf bifurcation of the steady-state to existing theory [Illing and Gauthier, Physica D 210, 180 (2005)]. We find good quantitative agreement of the predicted and the measured bifurcation threshold, bifurcation type and oscillation frequency. Numerical integration of the model yields quasiperiodic and high dimensional chaotic solutions (Lyapunov dimension approximately 13), which match qualitatively the observed device dynamics.}, Doi = {10.1063/1.2335814}, Key = {fds246432} } @article{fds246430, Author = {Agarwal, GS and Dey, TN and Gauthier, DJ}, Title = {Competition between electromagnetically induced transparency and Raman processes}, Journal = {Physical Review A}, Volume = {74}, Number = {4}, Pages = {043805}, Publisher = {American Physical Society (APS)}, Year = {2006}, Month = {October}, ISSN = {1050-2947}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRA74_043805_2006.pdf}, Abstract = {We present a theoretical formulation of the competition between electromagnetically induced transparency (EIT) and Raman processes. The latter become important when the medium can no longer be considered to be dilute. Unlike the standard formulation of EIT, we consider all fields applied and generated as interacting with both the transitions of the Î scheme. We solve the Maxwell equations for the net generated field using a fast-Fourier-transform technique and obtain predictions for the probe, control, and Raman fields. We show how the intensity of the probe field is depleted at higher atomic number densities due to the buildup of multiple Raman fields. Furthermore, we find that the generated fields and the input fields acquire oscillatory behavior as a function of the density of the medium due to dynamical coupling of the various Raman processes. © 2006 The American Physical Society.}, Doi = {10.1103/PhysRevA.74.043805}, Key = {fds246430} } @article{fds246328, Author = {Zhu, Z and Dawes, AMC and Gauthier, DJ}, Title = {Slow light via stimulated Brillouin scattering in optical fibers}, Journal = {Leos Summer Topical Meeting}, Pages = {38-39}, Publisher = {IEEE}, Year = {2006}, Month = {December}, ISSN = {1099-4742}, url = {http://dx.doi.org/10.1109/LEOSST.2004.1338669}, Abstract = {Optical-fiber-based slow-light techniques are reviewed. Slow light via stimulated Brillouin scattering (SBS) in optical fibers is discussed and recent progress in achieving broadband SBS slow light for high data-rate systems is presented. © 2006 IEEE.}, Doi = {10.1109/LEOSST.2004.1338669}, Key = {fds246328} } @article{fds246329, Author = {Dawes, AMC and Zhu, Z and Gauthier, DJ}, Title = {Improving the bandwidth of SBS-based slow-light delay}, Journal = {Conference on Lasers and Electro Optics and 2006 Quantum Electronics and Laser Science Conference, Cleo/Qels 2006}, Publisher = {IEEE}, Year = {2006}, Month = {December}, url = {http://dx.doi.org/10.1109/CLEO.2006.4628099}, Abstract = {Frequency modulating the pump laser in SBS slow-light delay systems increases the effective Brillouin bandwidth by nearly two orders of magnitude, making the fiber Brillouin amplifier technique applicable to all-optical controllable delay of Gb/s data. © 2006 Optical Society of America.}, Doi = {10.1109/CLEO.2006.4628099}, Key = {fds246329} } @article{fds246330, Author = {Zhu, Z and Gauthier, DJ}, Title = {XPM-induced pulse delay and advancement in optical fiber}, Journal = {Conference on Lasers and Electro Optics and 2006 Quantum Electronics and Laser Science Conference, Cleo/Qels 2006}, Publisher = {IEEE}, Year = {2006}, Month = {December}, url = {http://dx.doi.org/10.1109/CLEO.2006.4628520}, Abstract = {Cross-phase-modulation-induced pulse delay or advancement in an optical fiber is analyzed. It is shown that XPM and group-velocity mismatch can lead to controllable pulse delay or advancement with negligible frequency shift. © 2005 Optical Society of America.}, Doi = {10.1109/CLEO.2006.4628520}, Key = {fds246330} } @article{fds246327, Author = {Zhu, Z and Dawes, AMC and Gauthier, DJ and Zhang, L and Willner, AE}, Title = {12-GHz-bandwidth SBS slow light in optical fibers}, Journal = {2006 Optical Fiber Communication Conference, and the 2006 National Fiber Optic Engineers Conference}, Volume = {2006}, Year = {2006}, Month = {December}, Abstract = {We increased the bandwidth of SBS slow light in an optical fiber to 12.6 GHz. We delayed 75-ps pulses by up to 47 ps and studied the data pattern dependence of the broadband SBS slow-light system. © 2006 Optical Society of America.}, Key = {fds246327} } @article{fds246234, Author = {Gauthier, D}, Title = {Slow light in room-temperature optical waveguides}, Journal = {Optics Infobase Conference Papers}, Year = {2007}, ISSN = {2162-2701}, Key = {fds246234} } @article{fds246340, Author = {Aleksić, NB and Skarka, V and Timotijević, DV and Gauthier, D}, Title = {Self-stabilized spatiotemporal dynamics of dissipative light bullets generated from inputs without spherical symmetry in three-dimensional Ginzburg-Landau systems}, Journal = {Physical Review A}, Volume = {75}, Number = {6}, Publisher = {American Physical Society (APS)}, Year = {2007}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.75.061802}, Abstract = {In order to meet experimental conditions, the generation, evolution, and self-stabilization of optical dissipative light bullets from non-spherically-symmetric input pulses is studied. Steady-state solutions of the (3+1) -dimensional complex cubic-quintic Ginzburg-Landau equation are computed using the variational approach with a trial function asymmetric with respect to three transverse coordinates. The analytical stability criterion is extended to systems without spherical symmetry, allowing determination of the domain of dissipative parameters for stable solitonic solutions. The analytical predictions are confirmed by numerical evolution of the asymmetric input pulses toward stable dissipative light bullets. Once established, the dissipative light bullet remains surprisingly robust. © 2007 The American Physical Society.}, Doi = {10.1103/PhysRevA.75.061802}, Key = {fds246340} } @article{fds246209, Author = {Zhang, B and Yan, LS and Zhang, L and Willner, AE and Zhu, Z and Gauthier, DJ}, Title = {Broadband SBS slow light using simple spectrally-sliced pumping}, Journal = {2007 33rd European Conference and Exhibition of Optical Communication, Ecoc 2007}, Year = {2007}, Month = {January}, ISBN = {9783800730421}, Abstract = {We demonstrate broadband SBS slow-light using spectrally-sliced pumping. Both 2.5-Gb/s NRZ-OOK and NRZ-DPSK signals are delayed by maximum 170-ps with 4-dB power-penalty. Periodic spectrally-sliced multi-channel pumping scheme is proposed within a single slow-light medium.}, Key = {fds246209} } @article{fds246255, Author = {Gauthier, DJ}, Title = {Progress on stopped light and large-delay slow light in optical fibers}, Journal = {Optics Infobase Conference Papers}, Year = {2007}, Month = {January}, Abstract = {Recently, slow light was achieved in room temperature optical waveguides, which is accelerating the transition of this technique to applications. This paper reviews recent progress in obtaining large optically-controllable slow-light delays. © 2007 Optical Society of America.}, Key = {fds246255} } @article{fds246256, Author = {Dawes, AMC and Gauthier, DJ}, Title = {Using transverse patterns for all-optical switching}, Journal = {Optics Infobase Conference Papers}, Year = {2007}, Month = {January}, Abstract = {We observe that a transverse optical pattern changes orientation in the presence of an ultra-low-light-level beam. This switch displays transistor-like behavior. © 2007 Optical Society of America.}, Key = {fds246256} } @article{fds246257, Author = {Shi, Z and Boyd, RW and Gauthier, DJ and Dudley, CC}, Title = {Enhancing the spectral sensitivity and resolution of interferometers using slow-light media}, Journal = {Optics Infobase Conference Papers}, Year = {2007}, Month = {January}, Abstract = {We demonstrate experimentally that the spectral sensitivity and resolution of an interferometer can be greatly enhanced by introducing a slow-light medium into it with an enhancement factor equal to the group index of the medium. © 2006 Optical Society of America.}, Key = {fds246257} } @article{fds246258, Author = {Zhang, B and Fazal, I and Yan, LS and Zhang, L and A. Willner and E and Zhu, Z and Gauthier, DJ}, Title = {System performance of DPSK signals transmitted through broadband SBS-based slow light element and reduction of slow-light-induced data-pattern dependence}, Journal = {Optics Infobase Conference Papers}, Year = {2007}, Month = {January}, Abstract = {We demonstrate 42 ps delay on 10.7-Gb/s DPSK signals via SBS-based slow light. Slow-light-induced DPSK-data-pattern dependence is analyzed and its reduction results in 3-dB Q factor improvement. NRZ-DPSK and RZ-DPSK system performances are compared. © 2007 Optical Society of America.}, Key = {fds246258} } @article{fds246259, Author = {Shin, H and Schweinsberg, A and Gehring, G and Schwertz, K and Chang, HJ and Park, QH and Gauthier, DJ and Boyd, RW}, Title = {Pulse broadening or compression in fast-light pulse propagation through an erbium-doped fiber amplifier}, Journal = {Optics Infobase Conference Papers}, Year = {2007}, Month = {January}, Abstract = {Pulse broadening or compression in an Er3+-doped fiber amplifier is observed, and explained by gain recovery and pulse spectrum broadening effects. Maximal pulse advancement and minimal pulse distortion are obtained by optimizing these competing effects. © 2006 Optical Society of America.}, Key = {fds246259} } @article{fds246343, Author = {Zhao, X and Schaeffer, DG and Krassowska, W and Gauthier, DJ}, Title = {A model-independent technique for eigenvalue identification and its application in predicting cardiac alternans}, Journal = {Asme International Mechanical Engineering Congress and Exposition, Proceedings (Imece)}, Volume = {2}, Pages = {301-302}, Publisher = {ASME}, Year = {2007}, Month = {January}, url = {http://dx.doi.org/10.1115/IMECE2007-43380}, Abstract = {Copyright © 2007 by ASME. Predicting cardiac alternans is a crucial step toward detection and prevention of ventricular fibrillation, a heart rhythm disorder that kills hundreds of thousands of people in the US each year. According to the theory of dynamical systems, cardiac alternans is mediated by a period-doubling bifurcation, which is associated with variations in a characteristic eigenvalue. Thus, knowing the eigenvalues would allow one to predict the onset of alternans. The existing criteria for alternans either adopt unrealistically simple assumptions and thus produce erroneous predictions or rely on complicated intrinsic functions, which are not possible to measure experimentally. In this work, we present a model-independent technique to estimate a system's eigenvalues without requirements on the knowledge of the underlying dynamic model. The method is based on principal components analysis of a pseudo-state space; therefore, it allows one to compute the dominant eigenvalues of a system using the time history of a single measurable variable, e.g. The transmembrane voltage or the intracellular calcium concentration in cardiac experiments. Numerical examples based on a cardiac model verify the accuracy of the method. Thus, the technique provides a promising tool for predicting alternans in real-time experiments.}, Doi = {10.1115/IMECE2007-43380}, Key = {fds246343} } @article{fds246426, Author = {Zhu, Z and Dawes, AMC and Gauthier, DJ and Zhang, L and Willner, AE}, Title = {Broadband SBS slow light in an optical fiber}, Journal = {Journal of Lightwave Technology}, Volume = {25}, Number = {1}, Pages = {201-206}, Publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, Year = {2007}, Month = {January}, ISSN = {0733-8724}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/JLT25_201_2007.pdf}, Abstract = {In this paper, we investigate slow light via stimulated Brillouin scattering (SBS) in a room temperature optical fiber that is pumped by a spectrally broadened laser. Broadening the spectrum of the pump field increases the linewidth Δωp of the Stokes amplifying resonance, thereby increasing the slow-light bandwidth. One physical bandwidth limitation occurs when the linewidth becomes several times larger than the Brillouin frequency shift ΩB so that the anti-Stokes absorbing resonance substantially cancels out the Stokes amplifying resonance and, hence, the slow-light effect. We find that partial overlap of the Stokes and anti-Stokes resonances can actually lead to an enhancement of the slow-light delay-bandwidth product when Δωp ≃ 1.3ΩB. Using this general approach, we increase the Brillouin slow-light bandwidth to over 12 GHz from its nominal linewidth of ∼ 30 MHz obtained for monochromatic pumping. We controllably delay 75-ps-long pulses by up to 47 ps and study the data-pattern dependence of the broadband SBS slow-light system. © 2007 IEEE.}, Doi = {10.1109/JLT.2006.887188}, Key = {fds246426} } @article{fds246427, Author = {Gauthier, DJ and Boyd, RW}, Title = {Fast light, slow light and optical precursors: What does it all mean?}, Journal = {Photonics Spectra}, Volume = {41}, Number = {1}, Pages = {82-84+86-88+90}, Year = {2007}, Month = {January}, ISSN = {0731-1230}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PhotonicsSpectraFastLightSlowLight2007.pdf}, Abstract = {Einstein's special theory of relativity concerns the behavior of Maxwell's equations under coordinate transformations and has far-reaching consequences. In his public discussions of the theory, Einstein focuses on the concept of an "event," such as a spark caused by a lightning bolt and on how the event would be observed by people at various locations. Experiments conducted to date concerning how light travels are consistent with the special theory of relativity, although it remains difficult to show this. In some experiments, the pulse shape is such that it is exceedingly difficult to detect the pulse front and, hence, it may appear that the special theory has been violated. In other experiments especially designed to accentuate the pulse front, it has been shown that the information velocity is equal to c within the experimental uncertainties in both fast- and slow-light regimes.}, Key = {fds246427} } @article{fds246338, Author = {Gauthier, DJ}, Title = {Optical communications: Solitons go slow}, Journal = {Nature Photonics}, Volume = {1}, Number = {2}, Pages = {92-93}, Publisher = {Springer Nature}, Year = {2007}, Month = {February}, ISSN = {1749-4885}, url = {http://dx.doi.org/10.1038/nphoton.2006.91}, Doi = {10.1038/nphoton.2006.91}, Key = {fds246338} } @article{fds246425, Author = {Schaeffer, DG and Cain, JW and Gauthier, DJ and Kalb, SS and Oliver, RA and Tolkacheva, EG and Ying, W and Krassowska, W}, Title = {An ionically based mapping model with memory for cardiac restitution.}, Journal = {Bulletin of Mathematical Biology}, Volume = {69}, Number = {2}, Pages = {459-482}, Year = {2007}, Month = {Spring}, ISSN = {0092-8240}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17237915}, Abstract = {Many features of the sequence of action potentials produced by repeated stimulation of a patch of cardiac muscle can be modeled by a 1D mapping, but not the full behavior included in the restitution portrait. Specifically, recent experiments have found that (i) the dynamic and S1-S2 restitution curves are different (rate dependence) and (ii) the approach to steady state, which requires many action potentials (accommodation), occurs along a curve distinct from either restitution curve. Neither behavior can be produced by a 1D mapping. To address these shortcomings, ad hoc 2D mappings, where the second variable is a "memory" variable, have been proposed; these models exhibit qualitative features of the relevant behavior, but a quantitative fit is not possible. In this paper we introduce a new 2D mapping and determine a set of parameters for it that gives a quantitatively accurate description of the full restitution portrait measured from a bullfrog ventricle. The mapping can be derived as an asymptotic limit of an idealized ionic model in which a generalized concentration acts as a memory variable. This ionic basis clarifies how the present model differs from previous models. The ionic basis also provides the foundation for more extensive cardiac modeling: e.g., constructing a PDE model that may be used to study the effect of memory on propagation. The fitting procedure for the mapping is straightforward and can easily be applied to obtain a mathematical model for data from other experiments, including experiments on different species.}, Doi = {10.1007/s11538-006-9116-6}, Key = {fds246425} } @article{fds246428, Author = {Gauthier, DJ}, Title = {Solitons go Slow}, Journal = {An Invited Article in Nature Photonics}, Volume = {1}, Pages = {92}, Year = {2007}, Month = {February}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/NaturePhotonics1_92_2007.pdf}, Key = {fds246428} } @article{fds246429, Author = {Zhang, B and Yan, L and Fazal, I and Zhang, L and Willner, AE and Zhu, Z and Gauthier, DJ}, Title = {Slow light on Gbit/s differential-phase-shift-keying signals.}, Journal = {Optics Express}, Volume = {15}, Number = {4}, Pages = {1878-1883}, Year = {2007}, Month = {February}, ISSN = {1094-4087}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptExpress15_1878_2007.pdf}, Abstract = {We demonstrate, via simulation and experiment, slowing down of a phase-modulated optical signal. A 10.7-Gb/s NRZ-DPSK signal can be delayed by as much as 42 ps while still achieving error free via broadband SBS-based slow light. We further analyze the impact of slow-light-induced data-pattern dependence on both constructive and destructive demodulated ports. By detuning the SBS gain profile, we achieve 3-dB Q-factor improvement by the reduction of pattern dependence. Performance comparison between NRZ-DPSK and RZ-DPSK shows that robustness to slow-light-induced pattern dependence is modulation format dependent.}, Doi = {10.1364/oe.15.001878}, Key = {fds246429} } @article{fds246339, Author = {Ward, P and Gauthier, DJ and Boyd, RW}, Title = {Speed of light [3]}, Journal = {Photonics Spectra}, Volume = {41}, Number = {4}, Pages = {12}, Year = {2007}, Month = {April}, ISSN = {0731-1230}, Key = {fds246339} } @article{fds246422, Author = {Shi, Z and Boyd, RW and Gauthier, DJ and Dudley, CC}, Title = {Enhancing the spectral sensitivity of interferometers using slow-light media.}, Journal = {Optics Letters}, Volume = {32}, Number = {8}, Pages = {915-917}, Year = {2007}, Month = {April}, ISSN = {0146-9592}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptLett32_915_2007.pdf}, Abstract = {We demonstrate experimentally that the spectral sensitivity of an interferometer can be greatly enhanced by introducing a slow-light medium into it. The experimental results agree very well with theoretical predictions that the enhancement factor of the spectral sensitivity is equal to the group index n(g) of the slow-light medium.}, Doi = {10.1364/ol.32.000915}, Key = {fds246422} } @article{fds246423, Author = {Shin, H and Schweinsberg, A and Gehring, G and Schwertz, K and Chang, HJ and Boyd, RW and Park, Q-H and Gauthier, DJ}, Title = {Reducing pulse distortion in fast-light pulse propagation through an erbium-doped fiber amplifier.}, Journal = {Optics Letters}, Volume = {32}, Number = {8}, Pages = {906-908}, Year = {2007}, Month = {April}, ISSN = {0146-9592}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptLett32_906_2007.pdf}, Abstract = {When a pulse superposed on a cw background propagates through an erbium-doped fiber amplifier with a negative group velocity, either pulse broadening or pulse compression can be observed. These effects can be explained in terms of two competing mechanisms: gain recovery and pulse spectrum broadening. The distortion of the pulse shape caused by these effects depends on input pulse width, pump power, and background-to-pulse power ratio. With the proper choice of these three parameters, we can obtain significant pulse advancement with minimal pulse distortion.}, Doi = {10.1364/ol.32.000906}, Key = {fds246423} } @article{fds246336, Author = {Shi, Z and Boyd, RW and Gauthier, DJ and Dudley, CC}, Title = {Enhancing the spectral sensitivity of interferometers using slow-light media}, Journal = {Optics Letters}, Volume = {32}, Number = {8}, Pages = {915-917}, Year = {2007}, Month = {April}, url = {http://dx.doi.org/10.1364/OL.32.000915}, Abstract = {We demonstrate experimentally that the spectral sensitivity of an interferometer can be greatly enhanced by introducing a slow-light medium into it. The experimental results agree very well with theoretical predictions that the enhancement factor of the spectral sensitivity is equal to the group index ng of the slow-light medium. © 2007 Optical Society of America.}, Doi = {10.1364/OL.32.000915}, Key = {fds246336} } @article{fds246424, Author = {Zhao, X and Schaeffer, DG and Berger, CM and Gauthier, DJ}, Title = {Small-Signal Amplification of Period-Doubling Bifurcations in Smooth Iterated Maps.}, Journal = {Nonlinear Dynamics}, Volume = {48}, Number = {4}, Pages = {381-389}, Year = {2007}, Month = {Spring}, ISSN = {0924-090X}, url = {http://www.ncbi.nlm.nih.gov/pubmed/19112525}, Abstract = {Various authors have shown that, near the onset of a period-doubling bifurcation, small perturbations in the control parameter may result in much larger disturbances in the response of the dynamical system. Such amplification of small signals can be measured by a gain defined as the magnitude of the disturbance in the response divided by the perturbation amplitude. In this paper, the perturbed response is studied using normal forms based on the most general assumptions of iterated maps. Such an analysis provides a theoretical footing for previous experimental and numerical observations, such as the failure of linear analysis and the saturation of the gain. Qualitative as well as quantitative features of the gain are exhibited using selected models of cardiac dynamics.}, Doi = {10.1007/s11071-006-9092-2}, Key = {fds246424} } @article{fds246420, Author = {Shi, Z and Pant, R and Zhu, Z and Stenner, MD and Neifeld, MA and Gauthier, DJ and Boyd, RW}, Title = {Design of a tunable time-delay element using multiple gain lines for increased fractional delay with high data fidelity.}, Journal = {Optics Letters}, Volume = {32}, Number = {14}, Pages = {1986-1988}, Year = {2007}, Month = {July}, ISSN = {0146-9592}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptLett32_1986_2007.pdf}, Abstract = {A slow-light medium based on multiple, closely spaced gain lines is studied. The spacings and relative strengths of the gain lines are optimized by using the criteria of gain penalty and eye-opening penalty to maximize the fractional delay defined in terms of the best decision time for random pulse trains. Both numerical calculations and experiments show that an optimal design of a triple-gain-line medium can achieve a maximal fractional delay about twice that which can be obtained with a single-gain-line medium, at three times higher modulation bandwidth, while high data fidelity is still maintained.}, Doi = {10.1364/ol.32.001986}, Key = {fds246420} } @article{fds246421, Author = {Brown, NH and Dobrovolny, HM and Gauthier, DJ and Wolf, PD}, Title = {A fiber-based ratiometric optical cardiac mapping channel using a diffraction grating and split detector.}, Journal = {Biophysical Journal}, Volume = {93}, Number = {1}, Pages = {254-263}, Year = {2007}, Month = {July}, ISSN = {0006-3495}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17416627}, Abstract = {Optical fiber-based mapping systems are used to record the cardiac action potential (AP) throughout the myocardium. The optical AP contains a contraction-induced motion artifact (MA), which makes it difficult to accurately measure the action potential duration (APD). MA is removed by preventing contraction with electrical-mechanical uncoupling drugs, such as 2,3-butanedione monoxime (BDM). We designed a novel fiber-based ratiometric optical channel using a blue light emitting diode, a diffraction grating, and a split photodetector that can accurately measure the cardiac AP without the need for BDM. The channel was designed based on simulations using the optical design software ZEMAX. The channel has an electrical bandwidth of 150 Hz and an root mean-square dark noise of 742 muV. The channel successfully recorded the cardiac AP from the wall of five rabbit heart preparations without the use of BDM. After 20-point median filtering, the mean signal/noise ratio was 25.3 V/V. The APD measured from the base of a rabbit heart was 134 +/- 8.4 ms, compared to 137.6 +/- 3.3 ms from simultaneous microelectrode recordings. This difference was not statistically significant (p-value = 0.3). The quantity of MA removed was also measured using the motion ratio. The reduction in MA was significant (p-value = 0.0001). This fiber-based system is the first of its kind to enable optical APD measurements in the beating heart wall without the use of BDM.}, Doi = {10.1529/biophysj.106.101154}, Key = {fds246421} } @article{fds246419, Author = {Berger, CM and Zhao, X and Schaeffer, DG and Dobrovolny, HM and Krassowska, W and Gauthier, DJ}, Title = {Period-doubling bifurcation to alternans in paced cardiac tissue: crossover from smooth to border-collision characteristics.}, Journal = {Physical Review Letters}, Volume = {99}, Number = {5}, Pages = {058101}, Year = {2007}, Month = {August}, ISSN = {0031-9007}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17930795}, Abstract = {We investigate, both experimentally and theoretically, the period-doubling bifurcation to alternans in heart tissue. Previously, this phenomenon has been modeled with either smooth or border-collision dynamics. Using a modification of existing experimental techniques, we find a hybrid behavior: Very close to the bifurcation point, the dynamics is smooth, whereas further away it is border-collision-like. The essence of this behavior is captured by a model that exhibits what we call an unfolded border-collision bifurcation. This new model elucidates that, in an experiment, where only a limited number of data points can be measured, the smooth behavior of the bifurcation can easily be missed.}, Doi = {10.1103/physrevlett.99.058101}, Key = {fds246419} } @article{fds246418, Author = {Pant, R and Stenner, MD and Neifeld, MA and Shi, Z and Boyd, RW and Gauthier, DJ}, Title = {Maximizing the opening of eye diagrams for slow-light systems.}, Journal = {Applied Optics}, Volume = {46}, Number = {26}, Pages = {6513-6519}, Year = {2007}, Month = {September}, ISSN = {1559-128X}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/ApplOpt46_6513_2007.pdf}, Abstract = {We present a data-fidelity metric for quantifying distortion in slow-light optical pulse delay devices. We demonstrate the utility of this metric by applying it to the performance optimization of gain-based slow-light delay systems for Gaussian and super-Gaussian pulses. Symmetric Lorentzian double-line and triple-line gain systems are optimized and achieve maximum delay of 1.5 and 1.7 times the single-line gain system delay, respectively. The resulting double-line gain system design is qualitatively similar to the double-line gain system designed with a previous metric, but is tuned specifically to constrain data fidelity.}, Doi = {10.1364/ao.46.006513}, Key = {fds246418} } @article{fds246415, Author = {Berger, CM and Cain, JW and Socolar, JES and Gauthier, DJ}, Title = {Control of electrical alternans in simulations of paced myocardium using extended time-delay autosynchronization.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {76}, Number = {4 Pt 1}, Pages = {041917}, Year = {2007}, Month = {Fall}, ISSN = {1539-3755}, url = {http://www.ncbi.nlm.nih.gov/pubmed/17995036}, Abstract = {Experimental studies have linked alternans, an abnormal beat-to-beat alternation of cardiac action potential duration, to the genesis of lethal arrhythmias such as ventricular fibrillation. Prior studies have considered various closed-loop feedback control algorithms for perturbing interstimulus intervals in such a way that alternans is suppressed. However, some experimental cases are restricted in that the controller's stimuli must preempt those of the existing waves that are propagating in the tissue, and therefore only shortening perturbations to the underlying pacing are allowed. We present results demonstrating that a technique known as extended time-delay autosynchronization (ETDAS) can effectively control alternans locally while operating within the above constraints. We show that ETDAS, which has already been used to control chaos in physical systems, has numerous advantages over previously proposed alternans control schemes.}, Doi = {10.1103/physreve.76.041917}, Key = {fds246415} } @article{fds246333, Author = {Zhang, B and Fazal, I and Yan, LS and Zhang, L and Willner, AE and Zhu, Z and Gauthier, DJ}, Title = {System performance of DPSK signals transmitted through broadband SBS-based slow light element and reduction of slow-light-induced data-pattern dependence}, Journal = {Ofc/Nfoec 2007 Optical Fiber Communication and the National Fiber Optic Engineers Conference 2007}, Publisher = {IEEE}, Year = {2007}, Month = {December}, url = {http://dx.doi.org/10.1109/OFC.2007.4348657}, Abstract = {We demonstrate 42 ps delay on 10.7-Gb/s DPSK signals via SBS-based slow light. Slow-light-induced DPSK-data-pattern dependence is analyzed and its reduction results in 3-dB Q factor improvement. NRZ-DPSK and RZ-DPSK system performances are compared. © 2007 Optical Society of America.}, Doi = {10.1109/OFC.2007.4348657}, Key = {fds246333} } @article{fds246334, Author = {Gauthier, D}, Title = {Slow light in room-temperature optical waveguides}, Journal = {Conference on Lasers and Electro Optics Europe Technical Digest}, Publisher = {IEEE}, Year = {2007}, Month = {December}, url = {http://dx.doi.org/10.1109/CLEOE-IQEC.2007.4386826}, Doi = {10.1109/CLEOE-IQEC.2007.4386826}, Key = {fds246334} } @article{fds246335, Author = {Shin, H and Schweinsberg, A and Gehring, G and Schwertz, K and Hye, JC and Park, QH and Gauthier, DJ and Boyd, RW}, Title = {Pulse broadening or compression in fast-light pulse propagation through an erbium-doped fiber amplifier}, Journal = {Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series}, Publisher = {IEEE}, Year = {2007}, Month = {December}, url = {http://dx.doi.org/10.1109/QELS.2007.4431754}, Abstract = {Pulse broadening or compression in an Er3+-doped fiber amplifier is observed, and explained by gain recovery and pulse spectrum broadening effects. Maximal pulse advancement and minimal pulse distortion are obtained by optimizing these competing effects. © 2006 Optical Society of America.}, Doi = {10.1109/QELS.2007.4431754}, Key = {fds246335} } @article{fds246337, Author = {Illing, L and Gauthier, DJ and Roy, R}, Title = {Controlling optical chaos, spatio-temporal dynamics, and patterns}, Journal = {Advances in Atomic, Molecular and Optical Physics}, Volume = {54}, Number = {C}, Pages = {615-697}, Booktitle = {in Advanced in Atomic, Molecular, and Optical Physics (an invited chapter)}, Publisher = {Elsevier}, Editor = {P.R Berman and E. Arimondo and C. Lin}, Year = {2007}, Month = {December}, ISSN = {1049-250X}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/AdvancesAMO54_615_2007.pdf}, Abstract = {We describe how small perturbations applied to optical systems can be used to suppress or control optical chaos, spatio-temporal dynamics, and patterns. This research highlights the fact that complex behavior, such as chaos, has a beautiful and orderly underlying structure. We demonstrate that this orderly structure can be exploited for a variety of applications, such as stabilizing laser behavior in a regime where the device would normally produce erratic behavior, communicating information masked in a seemingly noise-like chaotic carrier, and improving the sensitivity of ultra-low-light level optical switches. © 2007 Elsevier Inc.}, Doi = {10.1016/S1049-250X(06)54010-8}, Key = {fds246337} } @article{fds246416, Author = {Zhu, Z and Gauthier, DJ and Boyd, RW}, Title = {Stored light in an optical fiber via stimulated Brillouin scattering.}, Journal = {Science (New York, N.Y.)}, Volume = {318}, Number = {5857}, Pages = {1748-1750}, Publisher = {American Association for the Advancement of Science (AAAS)}, Year = {2007}, Month = {December}, ISSN = {0036-8075}, url = {http://www.ncbi.nlm.nih.gov/pubmed/18079395}, Abstract = {We describe a method for storing sequences of optical data pulses by converting them into long-lived acoustic excitations in an optical fiber through the process of stimulated Brillouin scattering. These stored pulses can be retrieved later, after a time interval limited by the lifetime of the acoustic excitation. In the experiment reported here, smooth 2-nanosecond-long pulses are stored for up to 12 nanoseconds with good readout efficiency: 29% at 4-nanosecond storage time and 2% at 12 nanoseconds. This method thus can potentially store data packets that are many bits long. It can be implemented at any wavelength where the fiber is transparent and can be incorporated into existing telecommunication networks because it operates using only commercially available components at room temperature.}, Doi = {10.1126/science.1149066}, Key = {fds246416} } @article{fds246417, Author = {Greenberg, JA and Oriá, M and Dawes, AMC and Gauthier, DJ}, Title = {Absorption-induced trapping in an anisotropic magneto-optical trap.}, Journal = {Optics Express}, Volume = {15}, Number = {26}, Pages = {17699-17708}, Year = {2007}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/19551066}, Abstract = {We report on a simple anisotropic magneto-optical trap for neutral atoms that produces a large sample of cold atoms confined in a cylindrically-shaped volume with a high aspect ratio (100:1). Due to the large number of trapped atoms, the laser beams that propagate along the optically thick axis of the trap to cool the atoms are substantially attenuated. We demonstrate that the resulting intensity imbalance produces a net force that spatially localizes the atoms. This limits both the trap length and the total number of trapped atoms. Rotating the cooling beams by a small angle relative to the trap axis avoids the problem of attenuation, and atoms can be trapped throughout the entire available trapping volume. Numerical and experimental results are reported that demonstrate the effects of absorption in an anisotropic trap, and a steady-state, line-center optical path length of 55 is measured for a probe beam propagating along the length of the trap.}, Doi = {10.1364/oe.15.017699}, Key = {fds246417} } @article{fds311269, Author = {Zhao, X and Schaeffer, DG and Berger, CM and Krassowska, W and Gauthier, DJ}, Title = {Cardiac alternans arising from an unfolded border-collision bifurcation}, Journal = {2007 Proceedings of the Asme International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Detc2007}, Volume = {5 PART A}, Number = {4}, Pages = {223-232}, Year = {2008}, url = {http://dx.doi.org/10.1115/DETC2007-35304}, Abstract = {Following an electrical stimulus, the transmembrane voltage of cardiac tissue rises rapidly and remains at a constant value before returning to the resting value, a phenomenon known as an action potential. When the pacing rate of a periodic train of stimuli is increased above a critical value, the action potential undergoes a period-doubling bifurcation, where the resulting alternation of the action potential duration is known as alternans in the medical literature. In principle, a period-doubling bifurcation may occur through either a smooth or a nonsmooth mechanism. Previous experiments reveal that the bifurcation to alternans exhibits hybrid smooth/nonsmooth behaviors, which is due to large variations in the system's properties over a small interval of bifurcation parameter. To reproduce the experimentally observed hybrid behaviors, we have developed a model of alternans that exhibits an unfolded border-collision bifurcation. Excellent agreement between simulation of the model and experimental data suggests that features of the unfolded border-collision model should be included in modeling cardiac alternans. Copyright © 2007 by ASME.}, Doi = {10.1115/DETC2007-35304}, Key = {fds311269} } @article{fds246260, Author = {Gauthier, DJ and Juarez, AA and Vilaseca, R and Zhu, Z}, Title = {Room-temperature spectral hole burning via SBS}, Journal = {Optics Infobase Conference Papers}, Year = {2008}, Month = {January}, Abstract = {We observe spectral hole burning in a room-temperature optical fiber due to saturation of the stimulated Brillouin scattering process. The spectral hole is ~104 times narrower than the width of the resonance. © 2008 Optical Society of America.}, Key = {fds246260} } @article{fds246293, Author = {Gauthier, DJ}, Title = {Slow Light and Stored Light using SBS in an Optical Fiber}, Journal = {2008 34th European Conference on Optical Communication (Ecoc)}, Pages = {4 pages}, Publisher = {IEEE}, Year = {2008}, Month = {January}, ISBN = {978-1-4244-2228-9}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000300411200317&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Key = {fds246293} } @article{fds246348, Author = {Zhu, Z and Gauthier, DJ and Boyd, RW}, Title = {Light storage via stimulated brillouin scattering in an optical fiber}, Journal = {Optics and Photonics News}, Volume = {19}, Number = {12}, Pages = {40}, Publisher = {The Optical Society}, Year = {2008}, Month = {January}, ISSN = {1047-6938}, url = {http://dx.doi.org/10.1364/OPN.19.12.000040}, Abstract = {A simple method for storing optical pulses in a room-temperature optical fiber was demonstrated. The storage of optical data pulses is achieved by coherently transferring their information content to a slow-moving acoustic excitation in the fiber through their interaction with an additional optical 'write' pulse. The acoustic excitation is later converted back to the optical domain by interaction with a 'read' pulse. The write and read pulses should be much shorter than the data pulses and their area must equal π/2, to obtain high efficiency of the storage and retrieval processes. The method uses off-the-shelf components and operates at a wavelength of about 1.55 μm. Results for storage and retrieval of a sequence of multiple 2-ns data pulses demonstrate that the retrieved light replicates the input data stream with reasonable fidelity.}, Doi = {10.1364/OPN.19.12.000040}, Key = {fds246348} } @article{fds246410, Author = {Cabrera-Granado, E and Gauthier, DJ and Calderon, OG and Melle, S}, Title = {Observation of large 8-Gb/s SBS slow light delay with low distortion using an optimized gain profile}, Journal = {Optics Infobase Conference Papers}, Volume = {16}, Number = {16032}, Pages = {16032-16042}, Year = {2008}, Month = {January}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptExpress16_16032_2008.pdf}, Abstract = {We obtain over 3 pulse widths SBS slow light delay for an input pulse width of 125 ps. By optimizing the gain profile, the output-to-input pulse width ratio is less than 2.}, Key = {fds246410} } @article{fds246414, Author = {Dawes, AMC and Illing, L and Greenberg, JA and Gauthier, DJ}, Title = {All-optical switching with transverse optical patterns}, Journal = {Physical Review A}, Volume = {77}, Number = {1}, Pages = {013833}, Publisher = {American Physical Society (APS)}, Year = {2008}, Month = {January}, ISSN = {1050-2947}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/Switching_PRA_77_013833.pdf}, Abstract = {We demonstrate an all-optical switch that operates at ultra-low-light levels and exhibits several features necessary for use in optical switching networks. An input switching beam, wavelength λ, with an energy density of 10-2 photons per optical cross section [σ= λ2 (2π)] changes the orientation of a two-spot pattern generated via parametric instability in warm rubidium vapor. The instability is induced with less than 1 mW of total pump power and generates several μWs of output light. The switch is cascadable: the device output is capable of driving multiple inputs, and exhibits transistor-like signal-level restoration with both saturated and intermediate response regimes. Additionally, the system requires an input power proportional to the inverse of the response time, which suggests thermal dissipation does not necessarily limit the practicality of optical logic devices. © 2008 The American Physical Society.}, Doi = {10.1103/PhysRevA.77.013833}, Key = {fds246414} } @article{fds246413, Author = {Pant, R and Stenner, MD and Neifeld, MA and Gauthier, DJ}, Title = {Optimal pump profile designs for broadband SBS slow-light systems.}, Journal = {Optics Express}, Volume = {16}, Number = {4}, Pages = {2764-2777}, Year = {2008}, Month = {February}, ISSN = {1094-4087}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptExpress16_2764_2008.pdf}, Abstract = {We describe a methodology for designing the optimal gain profiles for gain-based, tunable, broadband, slow-light pulse delay devices based on stimulated Brillouin scattering. Optimal gain profiles are obtained under system constraints such as distortion, total pump power, and maximum gain. The delay performance of three candidate systems: Gaussian noise pump broadened (GNPB), optimal gain-only, and optimal gain+absorption are studied using Gaussian and super-Gaussian pulses. For the same pulse bandwidth, we find that the optimal gain+absorption medium improves the delay performance by 2.1 times the GNPB medium delay and 1.3 times the optimal gain-only medium delay for Gaussian pulses. For the super-Gaussian pulses the optimal gain-only medium provides a fractional pulse delay 1.8 times the GNPB medium delay.}, Doi = {10.1364/oe.16.002764}, Key = {fds246413} } @article{fds246412, Author = {Evertson, DW and Holcomb, MR and Eames, MC and Bray, M-A and Sidorov, VY and Xu, J and Wingard, H and Dobrovolny, HM and Woods, MC and Gauthier, DJ and Wikswo, JP}, Title = {High-resolution high-speed panoramic cardiac imaging system.}, Journal = {Ieee Transactions on Bio Medical Engineering}, Volume = {55}, Number = {3}, Pages = {1241-1243}, Year = {2008}, Month = {March}, ISSN = {0018-9294}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/IEEETransBME55_1241_2008.pdf}, Abstract = {A panoramic cardiac imaging system consisting of three high-speed CCD cameras has been developed to image the surface electrophysiology of a rabbit heart via fluorescence imaging using a voltage-sensitive fluorescent dye. A robust, unique mechanical system was designed to accommodate the three cameras and to adapt to the requirements of future experiments. A unified computer interface was created for this application - a single workstation controls all three CCD cameras, illumination, stimulation, and a stepping motor that rotates the heart. The geometric reconstruction algorithms were adapted from a previous cardiac imaging system. We demonstrate the system by imaging a polymorphic cardiac tachycardia.}, Doi = {10.1109/TBME.2007.912417}, Key = {fds246412} } @article{fds246278, Author = {Illing, L and Gauthier, DJ and Blakely, JN}, Title = {Controlling Fast Chaos in Optoelectronic Delay Dynamical Systems}, Pages = {405-425}, Booktitle = {Handbook of Chaos Control, 2nd Ed.}, Publisher = {Wiley-VCH Verlag GmbH & Co. KGaA}, Editor = {E. Schöll and H. G. Schuster}, Year = {2008}, Month = {May}, ISBN = {978-3-527-40605-0}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/IllingChaosHandbookPreprint2006.pdf}, Doi = {10.1002/9783527622313.ch19}, Key = {fds246278} } @article{fds304568, Author = {Cabrera-Granado, E and Calderón, OG and Melle, S and Gauthier, DJ}, Title = {Observation of large 10-Gb/s SBS slow light delay with low distortion using an optimized gain profile.}, Journal = {Optics Express}, Volume = {16}, Number = {20}, Pages = {16032-16042}, Year = {2008}, Month = {September}, url = {http://www.ncbi.nlm.nih.gov/pubmed/18825242}, Abstract = {An optimum SBS gain profile is designed to achieve better slow-light performance. It consists of a nearly flat-top profile with sharp edges. Tunable delays up to 3 pulse widths for 100-ps-long input pulses, corresponding to 10 Gb/s data rates, are found while keeping an output-input pulse-width ratio below 1.8. Bit-error-rate (BER) measurements performed for a non-return-to-zero modulation format demonstrates 28 ps of delay under error-free operation.}, Doi = {10.1364/oe.16.016032}, Key = {fds304568} } @article{fds246344, Author = {Dawes, AMC and Gauthier, DJ}, Title = {Transverse patterns for all-optical switching}, Journal = {Conference on Quantum Electronics and Laser Science (Qels) Technical Digest Series}, Booktitle = {Proceedings of The Ninth Rochester Conference on Coherence on Quantum Optics (CQO9)}, Publisher = {American Institute of Physics}, Address = {Melville, NY}, Editor = {N. Bigelow and J. Eberly and C. Stroud, Jr.}, Year = {2008}, Month = {September}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/cqo9.pdf}, Abstract = {Transverse optical patterns, generated by nonlinear interactions, rotate in the presence of a weak switch beam. Using an experimental system with increased symmetry, we observe that the switch can be actuated by ∼2100 photons. © 2008 Optical Society of America.}, Doi = {10.1109/QELS.2008.4553025}, Key = {fds246344} } @article{fds246409, Author = {Juarez, AA and Vilaseca, R and Zhu, Z and Gauthier, DJ}, Title = {Room-temperature spectral hole burning in an engineered inhomogeneously broadened resonance.}, Journal = {Optics Letters}, Volume = {33}, Number = {20}, Pages = {2374-2376}, Year = {2008}, Month = {October}, ISSN = {0146-9592}, url = {http://www.ncbi.nlm.nih.gov/pubmed/18923627}, Abstract = {We observe spectral hole burning in a room-temperature optical fiber pumped by a spectrally broadened pump beam. This beam drives the stimulated Brillouin process, creating an inhomogeneously broadened resonance in the material whose shape can be engineered by tailoring the beam's spectrum. A monochromatic saturating beam "burns" a narrow spectral hole that is approximately 10(4) times narrower than the inhomogeneous width of the resonance. This research paves the way toward agile optical information processing and storage using standard telecommunication components.}, Doi = {10.1364/ol.33.002374}, Key = {fds246409} } @article{fds246411, Author = {Zhao, X and Schaeffer, DG and Berger, CM and Krassowska, W and Gauthier, DJ}, Title = {Cardiac alternans arising from an unfolded border-collision bifurcation}, Journal = {Journal of Computational and Nonlinear Dynamics}, Volume = {3}, Number = {4}, Pages = {041004-041004}, Publisher = {ASME International}, Year = {2008}, Month = {October}, ISSN = {1555-1423}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000264934900004&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {Following an electrical stimulus, the transmembrane voltage of cardiac tissue rises rapidly and remains at a constant value before returning to the resting value, a phenomenon known as an action potential. When the pacing rate of a periodic train of stimuli is increased above a critical value, the action potential undergoes a period-doubling bifurcation, where the resulting alternation of the action potential duration is known as alternans in medical literature. Existing cardiac models treat alternans either as a smooth or as a border-collision bifurcation. However, recent experiments in paced cardiac tissue reveal that the bifurcation to altemans exhibits hybrid smooth/honsmooth behaviors, which can be qualitatively described by a model of so-called unfolded border-collision bifurcation. In this paper we obtain analytical solutions of the unfolded border-collision model and use it to explore the crossover between smooth and nonsmooth behaviors. Our analysis shows that the hybrid smooth/nonsmooth behavior is due to large variations in the system's properties over a small interval of the biurcation parameter, providing guidance for the development of future models. Copyright © 2008 by ASME.}, Doi = {10.1115/1.2960467}, Key = {fds246411} } @article{fds246345, Author = {Gauthier, DJ}, Title = {Slow light and stored light using SBS in an optical fiber}, Journal = {European Conference on Optical Communication, Ecoc}, Publisher = {IEEE}, Year = {2008}, Month = {December}, url = {http://dx.doi.org/10.1109/ECOC.2008.4729396}, Abstract = {Recently, slow light and stored light has been achieved in room temperature optical fibers at telecommunication wavelengths, which is accelerating the transition of these techniques to applications. © 2008 IEEE.}, Doi = {10.1109/ECOC.2008.4729396}, Key = {fds246345} } @article{fds246346, Author = {Cabrera-Granado, E and Gauthier, DJ}, Title = {Recent advancements in stimulated-Brillouin-scattering slow light}, Journal = {Optica Pura Y Aplicada}, Volume = {41}, Number = {4}, Pages = {313-323}, Year = {2008}, Month = {December}, ISSN = {0030-3917}, Abstract = {A review on the work performed by our group on slow light via Stimulating Brillouin scattering (SBS) is presented. We describe the fundamentals of the slow-light phenomena and how SBS can be used to obtain tunable optical delays in optical fibers. We then review the mechanisms to overcome the limitations imposed by the narrow SBS resonance bandwidth and to optimize the slow-light performance for data rates used in modern telecommunication networks. We also describe the process of coherent light storage in optical fibers based on SBS which paves the way to optical buffering applications. Finally, future perspectives of this exciting field of research are discussed. © Sociedad Española de Óptica.}, Key = {fds246346} } @article{fds246406, Author = {Gehring, GM and Boyd, RW and Gaeta, AL and Gauthier, DJ and Willner, AE}, Title = {Fiber-based slow-light technologies}, Journal = {Journal of Lightwave Technology}, Volume = {26}, Number = {23}, Pages = {3752-3762}, Publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, Year = {2008}, Month = {December}, ISSN = {0733-8724}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PTL26_3752_2008.pdf}, Abstract = {A review of current fiber-based technologies capable of producing slow-light effects is presented, with emphasis on the applicability of these technologies to telecommunications. We begin with a review of the basic concepts of phase velocity, group velocity, and group delay. We then present a survey of some of the figures of merit used to quantify the engineering properties of slow-light systems. We also present a description of several of the physical processes that are commonly used to induce a slow-light effect. Finally, a review of some recent advances in this field is presented. © 2008 IEEE.}, Doi = {10.1109/JLT.2008.2004883}, Key = {fds246406} } @article{fds246408, Author = {Cabrera Granado and E and Gauthier, DJ}, Title = {Recent advancements in SBS Slow Light}, Journal = {An Invited Article in Opt. Pura Apl.}, Volume = {41}, Pages = {313}, Year = {2008}, Month = {December}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/OptPuraApl41_313_2008.pdf}, Key = {fds246408} } @article{fds167526, Author = {Z. Zhu and D.J. Gauthier and A.L. Gaeta and R.W. Boyd}, Title = {Slow light in optical waveguides}, Pages = {37-57}, Booktitle = {an invited chapter in Slow Light: Science and Applications}, Publisher = {CRC Press}, Address = {Boca Raton}, Editor = {J. Khurgin and R.S. Tucker}, Year = {2008}, Month = {December}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/slow_light_waveguide.pdf}, Key = {fds167526} } @article{fds246352, Author = {Ravasio, A and Gauthier, D and Maia, FRNC and Billon, M and Caumes, JP and Garzella, D and Géléoc, M and Gobert, O and Hergott, JF and Pena, AM and al, E}, Title = {Single-shot diffractive imaging with a table-top femtosecond soft X-ray laser-harmonics source}, Journal = {Physical Review Letters}, Volume = {103}, Number = {2}, Year = {2009}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.103.028104}, Abstract = {Coherent x-ray diffractive imaging is a powerful method for studies on nonperiodic structures on the nanoscale. Access to femtosecond dynamics in major physical, chemical, and biological processes requires single-shot diffraction data. Up to now, this has been limited to intense coherent pulses from a free electron laser. Here we show that laser-driven ultrashort x-ray sources offer a comparatively inexpensive alternative. We present measurements of single-shot diffraction patterns from isolated nano-objects with a single 20fs pulse from a table-top high-harmonic x-ray laser. Images were reconstructed with a resolution of 119 nm from the single shot and 62 nm from multiple shots. © 2009 The American Physical Society.}, Doi = {10.1103/PhysRevLett.103.028104}, Key = {fds246352} } @article{fds318445, Author = {Dobrovolny, HM and Berger, CM and Brown, NH and Neu, WK and Gauthier, DJ}, Title = {Spatial heterogeneity of restitution properties and the onset of alternans.}, Journal = {Conference Proceedings : ... Annual International Conference of the Ieee Engineering in Medicine and Biology Society. Ieee Engineering in Medicine and Biology Society. Annual Conference}, Volume = {2009}, Pages = {4186-4189}, Year = {2009}, url = {http://dx.doi.org/10.1109/IEMBS.2009.5333929}, Abstract = {Traditionally, it was believed that cardiac rhythm stability was governed by the slope of the restitution curve (RC), which relates the duration of an action potential to the preceding diastolic interval. However, a single RC does not exist; rate-dependence leads to multiple distinct RCs. We measure spatial differences in the steady-state action potential duration (APD), as well as in three different RCs: the S1-S2 (SRC), constant-basic-cycle-length (BRC), and dynamic (DRC), and correlate these differences with the tissue's propensity to develop alternans. The results show that spatial differences in APD, SRC slope, and DRC slope are correlated with the tissue's propensity to exhibit alternans. These results may lead to a new diagnostic approach to identifying patients with vulnerability to arrhythmias, which will involve pacing at slow rates and analyzing spatial differences in restitution properties. ©2009 IEEE.}, Doi = {10.1109/IEMBS.2009.5333929}, Key = {fds318445} } @article{fds246266, Author = {Greenberg, JA and Gauthier, DJ}, Title = {Superradiance in an ultracold thermal vapor}, Journal = {Optics Infobase Conference Papers}, Year = {2009}, Month = {January}, Abstract = {We report on superradiant Rayleigh scattering in an anisotropic, cold thermal vapor. We identify threshold pump powers and atomic densities for entering the superradiant regime, and observe temporal correlations between light emitted in opposite directions. © 2009 Optical Society of America.}, Key = {fds246266} } @article{fds246351, Author = {Dobrovolny, HM and Berger, CM and Brown, NH and Neu, WK and Gauthier, DJ}, Title = {Spatial heterogeneity of restitution properties and the onset of alternans.}, Journal = {Conference Proceedings : ... Annual International Conference of the Ieee Engineering in Medicine and Biology Society. Ieee Engineering in Medicine and Biology Society. Annual Conference}, Volume = {2009}, Pages = {4186-4189}, Year = {2009}, Month = {January}, ISSN = {1557-170X}, url = {http://www.ncbi.nlm.nih.gov/pubmed/19964626}, Abstract = {Traditionally, it was believed that cardiac rhythm stability was governed by the slope of the restitution curve (RC), which relates the duration of an action potential to the preceding diastolic interval. However, a single RC does not exist; rate-dependence leads to multiple distinct RCs. We measure spatial differences in the steady-state action potential duration (APD), as well as in three different RCs: the S1-S2 (SRC), constant-basic-cycle-length (BRC), and dynamic (DRC), and correlate these differences with the tissue's propensity to develop alternans. The results show that spatial differences in APD, SRC slope, and DRC slope are correlated with the tissue's propensity to exhibit alternans. These results may lead to a new diagnostic approach to identifying patients with vulnerability to arrhythmias, which will involve pacing at slow rates and analyzing spatial differences in restitution properties.}, Doi = {10.1109/iembs.2009.5333929}, Key = {fds246351} } @article{fds246407, Author = {Greenberg, JA and Gauthier, DJ}, Title = {Transient dynamics and momentum redistribution in cold atoms via recoil-induced resonances}, Journal = {Physical Review A}, Volume = {79}, Number = {3}, Pages = {033414}, Publisher = {American Physical Society (APS)}, Year = {2009}, Month = {March}, ISSN = {1050-2947}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRA79_033414.pdf}, Abstract = {We use an optically dense anisotropic magneto-optical trap to study recoil-induced resonances (RIRs) in the transient high-gain regime. We find that two distinct mechanisms govern the atomic dynamics: the finite, frequency-dependent atomic response time and momentum-space population redistribution. At low input probe intensities, the residual Doppler width of the atoms, combined with the finite atomic response time, result in a linear transient hysteretic effect that modifies the locations, widths, and magnitudes of the resulting gain spectra depending on the sign of the scan chirp. When larger intensities (i.e., greater than a few μW/ cm2) are incident on the atomic sample for several μs, hole burning in the atomic sample momentum distribution leads to a coherent population redistribution that persists for approximately 100 μs. We propose using RIRs to engineer the atomic momentum distribution to enhance the nonlinear atom-photon coupling. We present a numerical model and compare the calculated and experimental results to verify our interpretation. © 2009 The American Physical Society.}, Doi = {10.1103/PhysRevA.79.033414}, Key = {fds246407} } @article{fds167525, Author = {D.J. Gauthier}, Title = {Superluminal communication in quantum mechanics}, Pages = {776-769}, Booktitle = {an invited article in Compendium of Quantum Physics: Concepts, Experiments, History and Philosophy}, Publisher = {Springer-Verlag}, Address = {Berlin}, Editor = {D. Greenberger and K. Hentschel and F. Weinert}, Year = {2009}, Month = {April}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/GauthierCompendiumPreprint2006.pdf}, Key = {fds167525} } @article{fds246405, Author = {Lefew, WR and Venakides, S and Gauthier, DJ}, Title = {Accurate description of optical precursors and their relation to weak-field coherent optical transients}, Journal = {Physical Review A}, Volume = {79}, Number = {6}, Pages = {063842}, Publisher = {American Physical Society (APS)}, Year = {2009}, Month = {June}, ISSN = {1050-2947}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRA79_063842_2009.pdf}, Abstract = {We study theoretically the propagation of a step-modulated optical field as it passes through a dispersive dielectric made up of a dilute collection of oscillators characterized by a single narrow-band resonance. The propagated field is given in terms of an integral of a Fourier type, which cannot be evaluated even for simple models of the dispersive dielectric. The fact that the oscillators have a low number density (dilute medium) and have a narrow-band resonance allows us to simplify the integrand. In this case, the integral can be evaluated exactly, although it is not possible using this method to separate out the transient part of the propagated field known as optical precursors. We also use an asymptotic method (saddle-point method) to evaluate the integral. The contributions to the integral related to the saddle points of the integrand give rise to the optical precursors. We obtain analytic expressions for the precursor fields and the domain over which the asymptotic method is valid. When combined to obtain the total transient field, we find that the agreement between the solutions obtained by the asymptotic and the exact methods is excellent. Our results demonstrate that precursors can persist for many nanoseconds and the chirp in the instantaneous frequency of the precursors can manifest itself in beats in the transmitted intensity. Our work strongly suggests that precursors have been observed in many previous experiments. © 2009 The American Physical Society.}, Doi = {10.1103/PhysRevA.79.063842}, Key = {fds246405} } @article{fds246404, Author = {Zhang, R and de S Cavalcante and HLD and Gao, Z and Gauthier, DJ and Socolar, JES and Adams, MM and Lathrop, DP}, Title = {Boolean chaos.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {80}, Number = {4 Pt 2}, Pages = {045202}, Year = {2009}, Month = {October}, url = {http://www.ncbi.nlm.nih.gov/pubmed/19905381}, Abstract = {We observe deterministic chaos in a simple network of electronic logic gates that are not regulated by a clocking signal. The resulting power spectrum is ultrawide band, extending from dc to beyond 2 GHz. The observed behavior is reproduced qualitatively using an autonomously updating Boolean model with signal propagation times that depend on the recent history of the gates and filtering of pulses of short duration, whose presence is confirmed experimentally. Electronic Boolean chaos may find application as an ultrawide-band source of radio waves.}, Doi = {10.1103/physreve.80.045202}, Key = {fds246404} } @article{fds246403, Author = {Boyd, RW and Gauthier, DJ}, Title = {Controlling the velocity of light pulses.}, Journal = {Science (New York, N.Y.)}, Volume = {326}, Number = {5956}, Pages = {1074-1077}, Year = {2009}, Month = {November}, ISSN = {0036-8075}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/Science326_1074_2009.pdf}, Abstract = {It is now possible to exercise a high degree of control over the velocity at which light pulses pass through material media. This velocity, known as the group velocity, can be made to be very different from the speed of light in a vacuum c. Specifically, the group velocity of light can be made much smaller than c, greater than c, or even negative. We present a survey of methods for establishing extreme values of the group velocity, concentrating especially on methods that work in room-temperature solids. We also describe some applications of slow light.}, Doi = {10.1126/science.1170885}, Key = {fds246403} } @article{fds246230, Author = {Dobrovolny, HM and Berger, CM and Brown, NH and Neu, WK and Gauthier, DJ}, Title = {Spatial heterogeneity of restitution properties and the onset of alternans.}, Journal = {Conference Proceedings : ... Annual International Conference of the Ieee Engineering in Medicine and Biology Society. Ieee Engineering in Medicine and Biology Society. Annual Conference}, Pages = {4186-4189}, Year = {2009}, Month = {December}, ISSN = {1557-170X}, url = {http://dx.doi.org/10.1109/IEMBS.2009.5333929}, Abstract = {Traditionally, it was believed that cardiac rhythm stability was governed by the slope of the restitution curve (RC), which relates the duration of an action potential to the preceding diastolic interval. However, a single RC does not exist; rate-dependence leads to multiple distinct RCs. We measure spatial differences in the steady-state action potential duration (APD), as well as in three different RCs: the S1-S2 (SRC), constant-basic-cycle-length (BRC), and dynamic (DRC), and correlate these differences with the tissue's propensity to develop alternans. The results show that spatial differences in APD, SRC slope, and DRC slope are correlated with the tissue's propensity to exhibit alternans. These results may lead to a new diagnostic approach to identifying patients with vulnerability to arrhythmias, which will involve pacing at slow rates and analyzing spatial differences in restitution properties.}, Doi = {10.1109/IEMBS.2009.5333929}, Key = {fds246230} } @article{fds246350, Author = {Boyd, RW and Gauthier, DJ and Narum, P}, Title = {Causality in superluminal pulse propagation}, Journal = {Lecture Notes in Physics}, Volume = {789}, Pages = {175-204}, Booktitle = {an invited chapter in Time in Quantum Mechanics II}, Publisher = {Springer Berlin Heidelberg}, Address = {Berlin}, Editor = {G. Muga and A. Ruschhaupt and A. del Campo}, Year = {2009}, Month = {December}, ISSN = {0075-8450}, url = {http://dx.doi.org/10.1007/978-3-642-03174-8_7}, Abstract = {We have reviewed recent theoretical and experimental research that establishes that pulses can propagate through material systems with superluminal or even negative group velocities. Nonetheless, these exotic propagation effects are fully compatible with established notion of causality. At a fundamental level, the nature of slow and fast light seems fairly well understood. But there still may be some surprises on the horizon.We noted in the body of this chapter that there seems to be no fundamental limit on how much one can delay a light pulse using slow-light methods, and in fact pulse delays as great as 80 pulse lengths have been observed [29]. Conversely, there seem to be severe limitations that limit the amount of advancement for a fast-light system to at most several pulse widths [71].1 But can these limitations be overcome? This is an intriguing question that merits further examination. © 2010 Springer-Verlag Berlin Heidelberg.}, Doi = {10.1007/978-3-642-03174-8_7}, Key = {fds246350} } @article{fds246353, Author = {Gauthier, D and Guizar-Sicairos, M and Ge, X and Boutu, W and Carré, B and Fienup, JR and Merdji, H}, Title = {Single-shot femtosecond x-ray holography using extended references}, Journal = {Physical Review Letters}, Volume = {105}, Number = {9}, Year = {2010}, ISSN = {0031-9007}, url = {http://dx.doi.org/10.1103/PhysRevLett.105.093901}, Abstract = {In the context of x-ray lensless imaging, we present a recent approach for Fourier transform holography based on the use of extended references. Major advances shown here rely on a high signal efficiency and on the direct image reconstruction of the object performed by a simple linear derivative. Moreover, the extended holographic reference is easy to manufacture and can be applied to a variety of imaging experiments. Here we demonstrate single-shot imaging with a table-top, laser-based coherent soft x-ray source. A spatial resolution of 110 nm was obtained with an integration time of 20 fs. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevLett.105.093901}, Key = {fds246353} } @article{fds246399, Author = {Oughstun, KE and Cartwright, NA and Gauthier, DJ and Jeong, H}, Title = {Optical precursors in the singular and weak dispersion limits}, Journal = {Journal of the Optical Society of America B}, Volume = {27}, Number = {8}, Pages = {1664-1670}, Publisher = {The Optical Society}, Year = {2010}, Month = {January}, ISSN = {0740-3224}, url = {http://hdl.handle.net/10161/5083 Duke open access}, Abstract = {The description of the precursor fields in a single-resonance Lorentz model dielectric is considered in the singular and weak dispersion limits. The singular dispersion limit is obtained as the damping approaches zero and the material dispersion becomes increasingly concentrated about the resonance frequency. The algebraic peak amplitude decay of the Brillouin precursor with propagation distance z>0 then changes from a z -1/2 to a z -1/3 behavior. The weak dispersion limit is obtained as the material density decreases to zero. The material dispersion then becomes vanishingly small everywhere and the precursors become increasingly compressed in the space-time domain immediately following the speed-of-light point (z, t)=(z,z/c). In order to circumvent the numerical difficulties introduced in this case, an approximate equivalence relation is derived that allows the propagated field evolution due to an ultrawideband signal to be calculated in an equivalent dispersive medium that is highly absorptive. © 2010 Optical Society of America.}, Doi = {10.1364/JOSAB.27.001664}, Key = {fds246399} } @article{fds246402, Author = {Cavalcante, HLDDS and Gauthier, DJ and Socolar, JES and Zhang, R}, Title = {On the origin of chaos in autonomous Boolean networks.}, Journal = {Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences}, Volume = {368}, Number = {1911}, Pages = {495-513}, Year = {2010}, Month = {January}, ISSN = {1364-503X}, url = {http://www.ncbi.nlm.nih.gov/pubmed/20008414}, Abstract = {We undertake a systematic study of the dynamics of Boolean networks to determine the origin of chaos observed in recent experiments. Networks with nodes consisting of ideal logic gates are known to display either steady states, periodic behaviour or an ultraviolet catastrophe where the number of logic-transition events circulating in the network per unit time grows as a power law. In an experiment, the non-ideal behaviour of the logic gates prevents the ultraviolet catastrophe and may lead to deterministic chaos. We identify certain non-ideal features of real logic gates that enable chaos in experimental networks. We find that short-pulse rejection and asymmetry between the logic states tend to engender periodic behaviour, at least for the simplest networks. On the other hand, we find that a memory effect termed 'degradation' can generate chaos. Our results strongly suggest that deterministic chaos can be expected in a large class of experimental Boolean-like networks. Such devices may find application in a variety of technologies requiring fast complex waveforms or flat power spectra, and can be used as a test-bed for fundamental studies of real-world Boolean-like networks.}, Doi = {10.1098/rsta.2009.0235}, Key = {fds246402} } @article{fds246401, Author = {Dawes, AMC and Gauthier, DJ and Schumacher, S and Kwong, NH and Binder, R and Smirl, AL}, Title = {Transverse optical patterns for ultra-low-light-level all-optical switching}, Journal = {Laser & Photonics Reviews}, Volume = {4}, Number = {2}, Pages = {221-243}, Publisher = {WILEY}, Year = {2010}, Month = {February}, ISSN = {1863-8880}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/LaserPhotonRev4_221_2010.pdf}, Abstract = {We review recent theoretical and experimental efforts toward developing an all-optical switch based on transverse optical patterns. Transverse optical patterns are formed when counterpropagating laser beams interact with a nonlinear medium. A perturbation, in the form of a weak switch beam injected into the nonlinear medium, controls the orientation of the generated patterns. Each state of the pattern orientation is associated with a state of the switch. That is, information is stored in the orientation state. A realization of this switch using a warm rubidium vapor shows that it can be actuated by as few as 600±40 photons with a response time of 5μs. Models of non-linear optical interactions in semiconductor quantum wells and microresonators suggest these systems are also suitable for use as fast all-optical switches using this same conceptual design, albeit at higher switching powers. © 2010 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.}, Doi = {10.1002/lpor.200810067}, Key = {fds246401} } @article{fds246400, Author = {Callan, KE and Illing, L and Gao, Z and Gauthier, DJ and Schöll, E}, Title = {Broadband chaos generated by an optoelectronic oscillator.}, Journal = {Physical Review Letters}, Volume = {104}, Number = {11}, Pages = {113901}, Year = {2010}, Month = {March}, url = {http://www.ncbi.nlm.nih.gov/pubmed/20366476}, Abstract = {We study an optoelectronic time-delay oscillator that displays high-speed chaotic behavior with a flat, broad power spectrum. The chaotic state coexists with a linearly stable fixed point, which, when subjected to a finite-amplitude perturbation, loses stability initially via a periodic train of ultrafast pulses. We derive approximate mappings that do an excellent job of capturing the observed instability. The oscillator provides a simple device for fundamental studies of time-delay dynamical systems and can be used as a building block for ultrawide-band sensor networks.}, Doi = {10.1103/physrevlett.104.113901}, Key = {fds246400} } @article{fds246398, Author = {Zhu, Y and Cabrera-Granado, E and Calderon, OG and Melle, S and Okawachi, Y and Gaeta, AL and Gauthier, DJ}, Title = {Competition between the modulation instability and stimulated Brillouin scattering in a broadband slow light device}, Journal = {Journal of Optics (United Kingdom)}, Volume = {12}, Number = {10}, Pages = {104019-104019}, Publisher = {IOP Publishing}, Year = {2010}, Month = {October}, ISSN = {2040-8978}, url = {http://hdl.handle.net/10161/5082 Duke open access}, Abstract = {We observe competition between the modulation instability (MI) and stimulated Brillouin scattering (SBS) in a 9.2 GHz broadband SBS slow light device, in which a standard 20 km long single-mode LEAF fibre is used as the SBS medium. We find that MI is dominant and depletes most of the pump power when we use an intense pump beam at ∼1.55 μm, where the LEAF fibre is anomalously dispersive. The dominance of the MI in the LEAF-fibre-based system suppresses the SBS gain, degrading the SBS slow light delay and limiting the SBS gain-bandwidth to 125 dB GHz. In a dispersion-shifted highly nonlinear fibre, the SBS slow light delay is improved due to the suppression of the MI, resulting in a gain-bandwidth product of 344 dB GHz, limited by our available pump power of 0.82 W. © 2010 IOP Publishing Ltd.}, Doi = {10.1088/2040-8978/12/10/104019}, Key = {fds246398} } @article{fds246267, Author = {Zhang, R and Zhu, Y and Wang, J and Gauthier, DJ}, Title = {Broadband slow light with a swept-frequency source}, Journal = {Optics Infobase Conference Papers}, Year = {2010}, Month = {December}, Abstract = {We demonstrate a pulse delay of 1.5 ns over a wide bandwidth via stimulated Brillouin scattering in an optical fiber pumped by a swept source with a sweep rate of 20 MHz/μs. © 2010 Optical Society of America.}, Key = {fds246267} } @article{fds246268, Author = {Zhu, Y and Wang, J and Zhang, R and Gauthier, DJ}, Title = {Observation of forward stimulated brillouin scattering in a standard highly-nonlinear fiber}, Journal = {Optics Infobase Conference Papers}, Year = {2010}, Month = {December}, Abstract = {We observe forward stimulated Brillouin scattering (FSBS) in a standard highly-nonlinear optical fiber a numerous acoustic resonance frequencies that occur between ~30 MHz to beyond the detection limit of 1.5 GHz. © 2010 Optical Society of America.}, Key = {fds246268} } @article{fds246269, Author = {Greenberg, JA and Gauthier, DJ}, Title = {Self-phase matched four-wave mixing in cold vapor}, Journal = {Optics Infobase Conference Papers}, Year = {2010}, Month = {December}, Abstract = {We demonstrate novel four-wave mixing processes in a cold vapor that arise due to atomic spatial self-organization. This leads to a reduced parametric oscillation threshold and a more rapid increase of gain with pump power. © 2010 Optical Society of America.}, Key = {fds246269} } @article{fds246270, Author = {Gauthier, DJ and Greenberg, JA}, Title = {Toward single-photon nonlinear optics via self-assembled ultracold atoms}, Journal = {Optics Infobase Conference Papers}, Year = {2010}, Month = {December}, Abstract = {We observe spontaneous parametric oscillation in a laser-driven cloud of cold atoms. The threshold for this instability is lowered dramatically due to self-assembled atomic gratings that allow for self-phase matching of atom-field wave mixing processes. © 2010 Optical Society of America.}, Key = {fds246270} } @article{fds246397, Author = {Zhang, R and Zhu, Y and Wang, J and Gauthier, DJ}, Title = {Slow light with a swept-frequency source.}, Journal = {Optics Express}, Volume = {18}, Number = {26}, Pages = {27263-27269}, Year = {2010}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/21197004}, Abstract = {ct: We introduce a new concept for stimulated-Brillouin-scattering-based slow light in optical fibers that is applicable for broadly-tunable frequency-swept sources. It allows slow light to be achieved, in principle, over the entire transparency window of the optical fiber. We demonstrate a slow light delay of 10 ns at 1.55 μm using a 10-m-long photonic crystal fiber with a source sweep rate of 400 MHz/μs and a pump power of 200 mW. We also show that there exists a maximal delay obtainable by this method, which is set by the SBS threshold, independent of sweep rate. For our fiber with optimum length, this maximum delay is ~38 ns, obtained for a pump power of 760 mW.}, Doi = {10.1364/oe.18.027263}, Key = {fds246397} } @article{fds246396, Author = {Zheng, H and Gauthier, DJ and Baranger, HU}, Title = {Waveguide QED: Many-body bound-state effects in coherent and Fock-state scattering from a two-level system}, Journal = {Physical Review A}, Volume = {82}, Number = {6}, Pages = {063816}, Publisher = {American Physical Society (APS)}, Year = {2010}, Month = {December}, ISSN = {1050-2947}, url = {http://hdl.handle.net/10161/8974 Duke open access}, Abstract = {Strong coupling between a two-level system (TLS) and bosonic modes produces dramatic quantum optics effects. We consider a one-dimensional continuum of bosons coupled to a single localized TLS, a system which may be realized in a variety of plasmonic, photonic, or electronic contexts. We present the exact many-body scattering eigenstate obtained by imposing open boundary conditions. Multiphoton bound states appear in the scattering of two or more photons due to the coupling between the photons and the TLS. Such bound states are shown to have a large effect on scattering of both Fock- and coherent-state wave packets, especially in the intermediate coupling-strength regime. We compare the statistics of the transmitted light with a coherent state having the same mean photon number: as the interaction strength increases, the one-photon probability is suppressed rapidly, and the two- and three-photon probabilities are greatly enhanced due to the many-body bound states. This results in non-Poissonian light. © 2010 The American Physical Society.}, Doi = {10.1103/PhysRevA.82.063816}, Key = {fds246396} } @article{fds246355, Author = {Zhu, Y and Kim, J and Gauthier, DJ}, Title = {Selective phase-matched bragg scattering for single-photon frequency conversion in a nonlinear waveguide}, Journal = {2011 Ieee Photonics Society Summer Topical Meeting Series}, Pages = {47-48}, Publisher = {IEEE}, Year = {2011}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/ProcIEEESummerTopicals2011_47.pdf}, Abstract = {We describe a design for phase-matched Bragg scattering for single-photon conversion between two arbitrary frequencies. The bandwidth of the Bragg scattering process is calculated and immunity against competing processes is discussed. © 2011 IEEE.}, Doi = {10.1109/PHOSST.2011.6000037}, Key = {fds246355} } @article{fds246383, Author = {Zhang, R and Greenberg, JA and Fischer, MC and Gauthier, DJ}, Title = {Controllable ultrabroadband slow light in a warm rubidium vapor}, Journal = {Journal of the Optical Society of America B}, Volume = {28}, Number = {11}, Pages = {2578-2583}, Publisher = {The Optical Society}, Year = {2011}, ISSN = {0740-3224}, url = {http://hdl.handle.net/10161/5105 Duke open access}, Abstract = {We study ultrabroadband slow light in a warm rubidium vapor cell. By working between the D1 and D2 transitions, we find a several-nanometer window centered at 788:4nm in which the group index is highly uniform and the absorption is small (<1%). We demonstrate that we can control the group delay by varying the temperature of the cell, and we observe a tunable fractional delay of 18 for pulses as short as 250 fs (6:9nm bandwidth) with a fractional broadening of only 0.65 and a power leakage of 55%. We find that a simple theoretical model is in excellent agreement with the experimental results. Using this model, we discuss the impact of the pulse's spectral characteristics on the distortion it incurs during propagation through the vapor. © 2011 Optical Society of America.}, Doi = {10.1364/JOSAB.28.002578}, Key = {fds246383} } @article{fds246391, Author = {Zhu, Y and Lee, M and Neifeld, MA and Gauthier, DJ}, Title = {High-fidelity, broadband stimulated-Brillouin-scattering-based slow light using fast noise modulation.}, Journal = {Optics Express}, Volume = {19}, Number = {2}, Pages = {687-697}, Year = {2011}, Month = {January}, url = {http://www.ncbi.nlm.nih.gov/pubmed/21263608}, Abstract = {We demonstrate a 5-GHz-broadband tunable slow-light device based on stimulated Brillouin scattering in a standard highly-nonlinear optical fiber pumped by a noise-current-modulated laser beam. The noisemodulation waveform uses an optimized pseudo-random distribution of the laser drive voltage to obtain an optimal flat-topped gain profile, which minimizes the pulse distortion and maximizes pulse delay for a given pump power. In comparison with a previous slow-modulation method, eye-diagram and signal-to-noise ratio (SNR) analysis show that this broadband slow-light technique significantly increases the fidelity of a delayed data sequence, while maintaining the delay performance. A fractional delay of 0.81 with a SNR of 5.2 is achieved at the pump power of 350 mW using a 2-km-long highly nonlinear fiber with the fast noise-modulation method, demonstrating a 50% increase in eye-opening and a 36% increase in SNR in the comparison.}, Doi = {10.1364/oe.19.000687}, Key = {fds246391} } @article{fds246392, Author = {Hwang, RY and Gauthier, DJ and Wallace, D and Afshari, NA}, Title = {Refractive changes after descemet stripping endothelial keratoplasty: a simplified mathematical model.}, Journal = {Investigative Ophthalmology & Visual Science}, Volume = {52}, Number = {2}, Pages = {1043-1054}, Year = {2011}, Month = {February}, url = {http://www.ncbi.nlm.nih.gov/pubmed/21051729}, Abstract = {PURPOSE: To develop a mathematical model that can predict refractive changes after Descemet stripping endothelial keratoplasty (DSEK). METHODS: A mathematical formula based on the Gullstrand eye model was generated to estimate the change in refractive power of the eye after DSEK. This model was applied to four DSEK cases retrospectively, to compare measured and predicted refractive changes after DSEK. RESULTS: The refractive change after DSEK is determined by calculating the difference in the power of the eye before and after DSEK surgery. The power of the eye post-DSEK surgery can be calculated with modified Gullstrand eye model equations that incorporate the change in the posterior radius of curvature and change in the distance between the principal planes of the cornea and lens after DSEK. Analysis of this model suggests that the ratio of central to peripheral graft thickness (CP ratio) and central thickness can have significant effect on refractive change where smaller CP ratios and larger graft thicknesses result in larger hyperopic shifts. This model was applied to four patients, and the average predicted hyperopic shift in the overall power of the eye was calculated to be 0.83 D. This change reflected in a mean of 93% (range, 75%-110%) of patients' measured refractive shifts. CONCLUSIONS: This simplified DSEK mathematical model can be used as a first step for estimating the hyperopic shift after DSEK. Further studies are necessary to refine the validity of this model.}, Doi = {10.1167/iovs.10-5839}, Key = {fds246392} } @article{fds246356, Author = {Oughstun, KE and Cartwright, NA and Gauthier, DJ and Jeong, H}, Title = {Optical precursors in the singular and weak dispersion limits: Reply to comment}, Journal = {Journal of the Optical Society of America B}, Volume = {28}, Number = {3}, Pages = {468-469}, Publisher = {The Optical Society}, Year = {2011}, Month = {March}, ISSN = {0740-3224}, url = {http://dx.doi.org/10.1364/JOSAB.28.000468}, Abstract = {The comment by Macke and Ségard [J. Opt. Soc. Am. B 28, 450-452 (2011)] of our recently published paper [J. Opt. Soc. Am. B 27, 1664-1670 (2010)] is shown here to be primarily due to a misunderstanding of the raison d'être of our paper. © 2011 Optical Society of America.}, Doi = {10.1364/JOSAB.28.000468}, Key = {fds246356} } @article{fds246390, Author = {Wang, J and Zhu, Y and Zhang, R and Gauthier, DJ}, Title = {FSBS resonances observed in a standard highly nonlinear fiber.}, Journal = {Optics Express}, Volume = {19}, Number = {6}, Pages = {5339-5349}, Year = {2011}, Month = {March}, ISSN = {1094-4087}, url = {http://hdl.handle.net/10161/5107 Duke open access}, Abstract = {Forward stimulated Brillouin scattering (FSBS) is observed in a standard 2-km-long highly nonlinear fiber. The frequency of FSBS arising from multiple radially guided acoustic resonances is observed up to gigahertz frequencies. The tight confinement of the light and acoustic field enhances the interaction and results in a large gain coefficient of 34.7 W(-1) at a frequency of 933.8 MHz. We also find that the profile on the anti-Stokes side of the pump beam have lineshapes that are asymmetric, which we show is due to the interference between FSBS and the optical Kerr effect. The measured FSBS resonance linewidths are found to increase linearly with the acoustic frequency. Based on this scaling, we conclude that dominant contribution to the linewidth is from surface damping due to the fiber jacket and structural nonuniformities along the fiber.}, Doi = {10.1364/oe.19.005339}, Key = {fds246390} } @article{fds246354, Author = {Zhu, Y and Wang, J and Zhang, R and Gauthier, DJ}, Title = {Interference of FSBS and Kerr effect in a standard highly-nonlinear fiber}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {7917}, Publisher = {SPIE}, Year = {2011}, Month = {April}, ISSN = {0277-786X}, url = {http://dx.doi.org/10.1117/12.876817}, Abstract = {We observe efficient forward stimulated Brillouin scattering (FSBS) in a standard 2-km highly-nonlinear optical fiber (NHLF), where we see multiple resonance peaks between 425 MHz to 1.1 GHz. The most efficient acoustooptical coupling appears for the 20th radially-guided acoustic mode at 933.8 MHz, which has maximum spatial overlapping with the tightly confined optical mode in the NHLF fiber. A large gain coefficient of 34.7 W-1 is obtained at this resonance when pumped with a 8 mW continuous-wave (cw) beam at 1550 nm, and an enhanced gain of 57.6 is obtained by using a pulsed pump beam at 80 mW. Interference between the FSBS process and the Kerr effect is observed to enhance the resonance and cause asymmetric profile for the observed resonances. © 2011 SPIE.}, Doi = {10.1117/12.876817}, Key = {fds246354} } @article{fds246389, Author = {Boyd, RW and Jha, A and Malik, M and O'Sullivan, C and Rodenburg, B and Gauthier, DJ}, Title = {Quantum key distribution in a high-dimensional state space: Exploiting the transverse degree of freedom of the photon}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {7948}, Pages = {79480L}, Publisher = {SPIE}, Year = {2011}, Month = {April}, ISSN = {0277-786X}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/BoydSPIE7948_79480L_2011.pdf}, Abstract = {We describe a procedure to construct a free-space quantum key distribution system that can carry many bits of information per photon. We also describe the current status of our laboratory implementation of these plans. © 2011 SPIE.}, Doi = {10.1117/12.873491}, Key = {fds246389} } @article{fds246388, Author = {Zhang, R and Zhu, Y and Wang, J and Gauthier, DJ}, Title = {Fiber-length dependence of slow light with a swept-frequency source}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {7949}, Pages = {794909}, Publisher = {SPIE}, Year = {2011}, Month = {May}, ISSN = {0277-786X}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/ZhangSPIE7949_794909_2011.pdf}, Abstract = {We study the slow light effect via stimulated Brillouin scattering (SBS) using broadly-tunable frequency-swept sources, such as that used in optical coherence tomography. Slow light can be achieved, in principle, over the entire transparency window of the optical fiber (many 100's of nm at telecommunication wavelengths). We demonstrate a SBS slow light delay of more than 1 ns over a wide bandwidth at 1.55 μm using a 2-km-long highly nonlinear fiber with a source sweep rate of 20 MHz/μs and a delay of 10 ns using a 10-m-long photonic crystal fiber with a sweep rate of 400 MHz/μs. We also find that, for a given sweep rate R, there is an optimum value of fiber length L to obtain the largest delay. © 2011 SPIE.}, Doi = {10.1117/12.876805}, Key = {fds246388} } @article{fds246393, Author = {Jeong, H and Dawes, AMC and Gauthier, DJ}, Title = {Carrier-frequency dependence of a step-modulated pulse propagating through a weakly dispersive single narrow-resonance absorber}, Journal = {Journal of Modern Optics}, Volume = {58}, Number = {10}, Pages = {865-872}, Publisher = {Informa UK Limited}, Year = {2011}, Month = {June}, ISSN = {0950-0340}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/JModOpt58_865_2011.pdf}, Abstract = {We observe interference between the optical precursors and the main signal for small optical depth α0L∼1, in which the main signal cannot be entirely absorbed. Since the main signal oscillates at the carrier frequency of the input pulse and precursors oscillate at medium resonance frequency, in our case carrier frequency dependence of the total transmitted field is observed as a form of modulation patterns oscillating at the detuning frequency. To distinguish between the Sommerfeld and Brillouin precursors for the case of weakly dispersive off-resonance medium, we utilize asymptotic precursor theory under the assumption of small detuning. © 2011 Taylor & Francis.}, Doi = {10.1080/09500340.2011.575961}, Key = {fds246393} } @article{fds246357, Author = {Boulanger, B and Cundiff, ST and Gauthier, DJ and Karlsson, M and Lu, YQ and Norwood, RA and Skryabin, D and Taira, T}, Title = {Focus issue introduction: Nonlinear optics}, Journal = {Optical Materials Express}, Volume = {1}, Number = {7}, Pages = {1393-1398}, Publisher = {The Optical Society}, Year = {2011}, Month = {November}, ISSN = {2159-3930}, url = {http://dx.doi.org/10.1364/OME.1.001393}, Abstract = {It is now fifty years since the original observation of second harmonic generation ushered in the field of nonlinear optics, close on the heels of the invention of the laser. This feature issue celebrates this anniversary with papers that span the range from new nonlinear optical materials, through the increasingly novel methods that have been developed for phase matching, to emerging areas such as nonlinear metamaterials and plasmonic enhancement of optical properties. It is clear that the next fifty years of nonlinear optics will witness a proliferation of new applications with increasing technological impact. © 2011 Optical Society of America.}, Doi = {10.1364/OME.1.001393}, Key = {fds246357} } @article{fds246358, Author = {Boulanger, B and Cundiff, ST and Gauthier, DJ and Karlsson, M and Lu, Y-Q and Norwood, RA and Skryabin, D and Taira, T}, Title = {Focus issue introduction: nonlinear optics.}, Journal = {Optics Express}, Volume = {19}, Number = {23}, Pages = {23561-23566}, Year = {2011}, Month = {November}, ISSN = {1094-4087}, url = {http://dx.doi.org/10.1364/oe.19.023561}, Abstract = {It is now fifty years since the original observation of second harmonic generation ushered in the field of nonlinear optics, close on the heels of the invention of the laser. This feature issue celebrates this anniversary with papers that span the range from new nonlinear optical materials, through the increasingly novel methods that have been developed for phase matching, to emerging areas such as nonlinear metamaterials and plasmonic enhancement of optical properties. It is clear that the next fifty years of nonlinear optics will witness a proliferation of new applications with increasing technological impact.}, Doi = {10.1364/oe.19.023561}, Key = {fds246358} } @article{fds246385, Author = {Rosin, DP and Callan, KE and Gauthier, DJ and Schöll, E}, Title = {Pulse-train solutions and excitability in an optoelectronic oscillator}, Journal = {Epl (Europhysics Letters)}, Volume = {96}, Number = {3}, Pages = {34001-34001}, Publisher = {IOP Publishing}, Year = {2011}, Month = {November}, ISSN = {0295-5075}, url = {http://hdl.handle.net/10161/5102 Duke open access}, Abstract = {We study an optoelectronic time-delay oscillator with bandpass filtering for different values of the filter bandwidth. Our experiments show novel pulse-train solutions with pulse widths that can be controlled over a three-order-of-magnitude range, with a minimum pulse width of ∼150 ps. The equations governing the dynamics of our optoelectronic oscillator are similar to the FitzHugh-Nagumo model from neurodynamics with delayed feedback in the excitable and oscillatory regimes. Using a nullclines analysis, we derive an analytical proportionality between pulse width and the low-frequency cutoff of the bandpass filter, which is in agreement with experiments and numerical simulations. Furthermore, the nullclines help to describe the shape of the waveforms. © Europhysics Letters Association.}, Doi = {10.1209/0295-5075/96/34001}, Key = {fds246385} } @article{fds246386, Author = {Lee, M and Zhu, Y and Gauthier, DJ and Gehm, ME and Neifeld, MA}, Title = {Information-theoretic analysis of a stimulated-Brillouin-scattering-based slow-light system.}, Journal = {Applied Optics}, Volume = {50}, Number = {32}, Pages = {6063-6072}, Year = {2011}, Month = {November}, ISSN = {1559-128X}, url = {http://hdl.handle.net/10161/5103 Duke open access}, Abstract = {We use an information-theoretic method developed by Neifeld and Lee [J. Opt. Soc. Am. A 25, C31 (2008)] to analyze the performance of a slow-light system. Slow-light is realized in this system via stimulated Brillouin scattering in a 2 km-long, room-temperature, highly nonlinear fiber pumped by a laser whose spectrum is tailored and broadened to 5 GHz. We compute the information throughput (IT), which quantifies the fraction of information transferred from the source to the receiver and the information delay (ID), which quantifies the delay of a data stream at which the information transfer is largest, for a range of experimental parameters. We also measure the eye-opening (EO) and signal-to-noise ratio (SNR) of the transmitted data stream and find that they scale in a similar fashion to the information-theoretic method. Our experimental findings are compared to a model of the slow-light system that accounts for all pertinent noise sources in the system as well as data-pulse distortion due to the filtering effect of the SBS process. The agreement between our observations and the predictions of our model is very good. Furthermore, we compare measurements of the IT for an optimal flattop gain profile and for a Gaussian-shaped gain profile. For a given pump-beam power, we find that the optimal profile gives a 36% larger ID and somewhat higher IT compared to the Gaussian profile. Specifically, the optimal (Gaussian) profile produces a fractional slow-light ID of 0.94 (0.69) and an IT of 0.86 (0.86) at a pump-beam power of 450 mW and a data rate of 2.5 Gbps. Thus, the optimal profile better utilizes the available pump-beam power, which is often a valuable resource in a system design.}, Doi = {10.1364/ao.50.006063}, Key = {fds246386} } @article{fds246387, Author = {Greenberg, JA and Schmittberger, BL and Gauthier, DJ}, Title = {Bunching-induced optical nonlinearity and instability in cold atoms [Invited].}, Journal = {Optics Express}, Volume = {19}, Number = {23}, Pages = {22535-22549}, Year = {2011}, Month = {November}, url = {http://www.ncbi.nlm.nih.gov/pubmed/22109132}, Abstract = {We report a new nonlinear optical process that occurs in a cloud of cold atoms at low-light-levels when the incident optical fields simultaneously polarize, cool, and spatially-organize the atoms. We observe an extremely large effective fifth-order nonlinear susceptibility of χ(⁵) = 7.6 × 10⁻¹⁵ (m/V)⁴, which results in efficient Bragg scattering via six-wave mixing, slow group velocities (∼ c/10⁵), and enhanced atomic coherence times (> 100 μs). In addition, this process is particularly sensitive to the atomic temperatures, and provides a new tool for in-situ monitoring of the atomic momentum distribution in an optical lattice. For sufficiently large light-matter couplings, we observe an optical instability for intensities as low as ∼ 1 mW/cm² in which new, intense beams of light are generated and result in the formation of controllable transverse optical patterns.}, Doi = {10.1364/OE.19.022535}, Key = {fds246387} } @article{fds246384, Author = {Zheng, H and Gauthier, DJ and Baranger, HU}, Title = {Cavity-free photon blockade induced by many-body bound states.}, Journal = {Physical Review Letters}, Volume = {107}, Number = {22}, Pages = {223601}, Year = {2011}, Month = {November}, url = {http://www.ncbi.nlm.nih.gov/pubmed/22182028}, Abstract = {The manipulation of individual, mobile quanta is a key goal of quantum communication; to achieve this, nonlinear phenomena in open systems can play a critical role. We show theoretically that a variety of strong quantum nonlinear phenomena occur in a completely open one-dimensional waveguide coupled to an N-type four-level system. We focus on photon blockade and the creation of single-photon states in the absence of a cavity. Many-body bound states appear due to the strong photon-photon correlation mediated by the four-level system. These bound states cause photon blockade, which can generate a sub-Poissonian single-photon source.}, Doi = {10.1103/physrevlett.107.223601}, Key = {fds246384} } @article{fds246274, Author = {Boyd, RW and Shin, H and Malik, M and O'Sullivan, C and Chan, KWC and Chang, HJ and Gauthier, DJ and Jha, A and Leach, J and Murugkar, S and Rodenburg, B}, Title = {Applications of nonlinear optics in quantum imaging and quantum communication}, Journal = {Optics Infobase Conference Papers}, Year = {2011}, Month = {December}, Abstract = {The nonlinear optical process of spontaneous parametric downconversion is a standard procedure for generating entangled photons. Entanglement is a crucial resource for quantum information studies. We describe our recent results including the application of entangled photons to superresolution and to quantum communication. NLO/ISOM/ODS © 2011 OSA.}, Key = {fds246274} } @article{fds246382, Author = {Cohen, SD and Cavalcante, HLDDS and Gauthier, DJ}, Title = {Subwavelength position sensing using nonlinear feedback and wave chaos.}, Journal = {Physical Review Letters}, Volume = {107}, Number = {25}, Pages = {254103}, Year = {2011}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/22243079}, Abstract = {We demonstrate a position-sensing technique that relies on the inherent sensitivity of chaos, where we illuminate a subwavelength object with a complex structured radio-frequency field generated using wave chaos and nonlinear feedback. We operate the system in a quasiperiodic state and analyze changes in the frequency content of the scalar voltage signal in the feedback loop. This allows us to extract the object's position with a one-dimensional resolution of ~λ/10,000 and a two-dimensional resolution of ~λ/300, where λ is the shortest wavelength of the illuminating source.}, Doi = {10.1103/physrevlett.107.254103}, Key = {fds246382} } @article{fds246283, Author = {Callan, KE and Illing, L and Gauthier, DJ}, Title = {Broadband Chaos}, Series = {Reviews in Nonlinear Dynamics and Complexity}, Pages = {317-332}, Booktitle = {Nonlinear Laser Dynamics: From Quantum Dots to Cryptography}, Publisher = {Wiley-VCH Verlag GmbH & Co. KGaA}, Address = {Weinheim}, Editor = {K. Luege}, Year = {2012}, Month = {January}, ISBN = {978-3-527-41100-9}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/BroadbandChaos_Gauthier.pdf}, Doi = {10.1002/9783527639823.ch13}, Key = {fds246283} } @article{fds246381, Author = {Greenberg, JA and Gauthier, DJ}, Title = {High-order optical nonlinearity at low light levels}, Journal = {Epl (Europhysics Letters)}, Volume = {98}, Number = {2}, Pages = {24001-24001}, Publisher = {IOP Publishing}, Year = {2012}, Month = {April}, ISSN = {0295-5075}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/EPL98_24001_2012.pdf}, Abstract = {We observe a nonlinear optical process in a gas of cold atoms that simultaneously displays the largest reported fifth-order nonlinear susceptibility χ (5)=1.9×10 - 12 (m/V) 4 and high transparency. The nonlinearity results from the simultaneous cooling and crystallization of the gas, and gives rise to efficient Bragg scattering in the form of six-wave mixing at low light levels. For large atom-photon coupling strengths, the back-action of the scattered fields influences the light-matter dynamics. We confirm this interpretation by investigating the nonlinearity for different polarization configurations. In addition, we demonstrate excellent agreement between our experimental measurements and a theoretical model with no free parameters, and compare our results to those obtained using alternative approaches. This system may have important applications in many-body physics, quantum information processing, and multidimensional soliton formation. © Europhysics Letters Association 2012.}, Doi = {10.1209/0295-5075/98/24001}, Key = {fds246381} } @article{fds246379, Author = {Zheng, H and Gauthier, DJ and Baranger, HU}, Title = {Strongly correlated photons generated by coupling a three- or four-level system to a waveguide}, Journal = {Physical Review A}, Volume = {85}, Number = {4}, Pages = {043832}, Publisher = {American Physical Society (APS)}, Year = {2012}, Month = {April}, ISSN = {1050-2947}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRA85_043832_2012.pdf}, Abstract = {We study the generation of strongly correlated photons by coupling an atom to photonic quantum fields in a one-dimensional waveguide. Specifically, we consider a three-level or four-level system for the atom. Photon-photon bound states emerge as a manifestation of the strong photon-photon correlation mediated by the atom. Effective repulsive or attractive interaction between photons can be produced, causing either suppressed multiphoton transmission (photon blockade) or enhanced multiphoton transmission (photon-induced tunneling). As a result, nonclassical light sources can be generated on demand by sending coherent states into the proposed system. We calculate the second-order correlation function of the transmitted field and observe bunching and antibunching caused by the bound states. Furthermore, we demonstrate that the proposed system can produce photon pairs with a high degree of spectral entanglement, which have a large capacity for carrying information and are important for large-alphabet quantum communication. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevA.85.043832}, Key = {fds246379} } @article{fds246380, Author = {Poutrina, E and Ciracì, C and Gauthier, DJ and Smith, DR}, Title = {Enhancing four-wave-mixing processes by nanowire arrays coupled to a gold film.}, Journal = {Optics Express}, Volume = {20}, Number = {10}, Pages = {11005-11013}, Year = {2012}, Month = {May}, url = {http://www.ncbi.nlm.nih.gov/pubmed/22565723}, Abstract = {We consider the process of four-wave mixing in an array of gold nanowires strongly coupled to a gold film. Using full-wave simulations, we perform a quantitative comparison of the four-wave mixing efficiency associated with a bare film and films with nanowire arrays. We find that the strongly localized surface plasmon resonances of the coupled nanowires provide an additional local field enhancement that, along with the delocalized surface plasmon of the film, produces an overall four-wave mixing efficiency enhancement of up to six orders of magnitude over that of the bare film. The enhancement occurs over a wide range of excitation angles. The film-coupled nanowire array is easily amenable to nanofabrication, and could find application as an ultra-compact component for integrated photonic and quantum optic systems.}, Doi = {10.1364/oe.20.011005}, Key = {fds246380} } @article{fds246378, Author = {Leach, J and Bolduc, E and Gauthier, DJ and Boyd, RW}, Title = {Secure information capacity of photons entangled in many dimensions}, Journal = {Physical Review A}, Volume = {85}, Number = {6}, Pages = {060304(R)}, Publisher = {American Physical Society (APS)}, Year = {2012}, Month = {June}, ISSN = {1050-2947}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRA85_060304_2012.pdf}, Abstract = {We quantify precisely the maximum secure information capacity of photons entangled in high dimensions for entanglement in the orbital angular momentum and angular degrees of freedom. Our analysis takes careful account of the influence of experimental imperfections, such as nonunity detection efficiency, on the degree of Einstein-Podolsky-Rosen (EPR) entanglement and hence on the secure information capacity of the photon pairs. We find that there is is an optimal dimension that maximizes the secure information capacity whose value can be predicted analytically from the knowledge of only a few experimental parameters. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevA.85.060304}, Key = {fds246378} } @article{fds246377, Author = {Greenberg, JA and Gauthier, DJ}, Title = {Steady-state, cavityless, multimode superradiance in a cold vapor}, Journal = {Physical Review A}, Volume = {86}, Number = {1}, Pages = {5 pages}, Publisher = {AMER PHYSICAL SOC}, Year = {2012}, Month = {July}, ISSN = {1050-2947}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/PRA86_013823_2012.pdf}, Abstract = {We demonstrate steady-state, mirrorless superradiance in a cold vapor pumped by weak optical fields. Beyond a critical pump intensity of 1 mW/cm2, the vapor spontaneously transforms into a spatially self-organized state: a density grating forms. Scattering of the pump beams off this grating generates a pair of new, intense optical fields that act back on the vapor to enhance the atomic organization. We map out experimentally the superradiant phase transition boundary and show that it is well described by our theoretical model. The resulting superradiant emission is nearly coherent, persists for several seconds, displays strong temporal correlations between the various modes, and has a coherence time of several hundred μs. This system therefore has applications in fundamental studies of many-body physics with long-range interactions as well as all-optical and quantum information processing. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevA.86.013823}, Key = {fds246377} } @article{fds304569, Author = {Greenberg, JA and Gauthier, DJ}, Title = {Steady-state, cavityless, multimode superradiance in a cold vapor}, Journal = {Physical Review A}, Volume = {86}, Number = {1}, Publisher = {American Physical Society (APS)}, Year = {2012}, Month = {July}, ISSN = {1050-2947}, url = {http://dx.doi.org/10.1103/PhysRevA.86.013823}, Abstract = {We demonstrate steady-state, mirrorless superradiance in a cold vapor pumped by weak optical fields. Beyond a critical pump intensity of 1 mW/cm2, the vapor spontaneously transforms into a spatially self-organized state: a density grating forms. Scattering of the pump beams off this grating generates a pair of new, intense optical fields that act back on the vapor to enhance the atomic organization. We map out experimentally the superradiant phase transition boundary and show that it is well described by our theoretical model. The resulting superradiant emission is nearly coherent, persists for several seconds, displays strong temporal correlations between the various modes, and has a coherence time of several hundred μs. This system therefore has applications in fundamental studies of many-body physics with long-range interactions as well as all-optical and quantum information processing. © 2012 American Physical Society.}, Doi = {10.1103/PhysRevA.86.013823}, Key = {fds304569} } @article{fds246376, Author = {Cohen, SD and Gauthier, DJ}, Title = {A pseudo-matched filter for chaos.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {22}, Number = {3}, Pages = {033148}, Year = {2012}, Month = {September}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23020487}, Abstract = {A matched filter maximizes the signal-to-noise ratio of a signal. In the recent work of Corron et al. [Chaos 20, 023123 (2010)], a matched filter is derived for the chaotic waveforms produced by a piecewise-linear system. This system produces a readily available binary symbolic dynamics that can be used to perform correlations in the presence of large amounts of noise using the matched filter. Motivated by these results, we describe a pseudo-matched filter, which operates similarly to the original matched filter. It consists of a notch filter followed by a first-order, low-pass filter. We compare quantitatively the matched filter's performance to that of our pseudo-matched filter using correlation functions. On average, the pseudo-matched filter performs with a correlation signal-to-noise ratio that is 2.0 dB below that of the matched filter. Our pseudo-matched filter, though somewhat inferior in comparison to the matched filter, is easily realizable at high speed (>1 GHz) for potential radar applications.}, Doi = {10.1063/1.4754437}, Key = {fds246376} } @article{fds246374, Author = {Rosin, DP and Rontani, D and Gauthier, DJ and Schöll, E}, Title = {Excitability in autonomous Boolean networks}, Journal = {Epl (Europhysics Letters)}, Volume = {100}, Number = {3}, Pages = {30003-30003}, Publisher = {IOP Publishing}, Year = {2012}, Month = {November}, ISSN = {0295-5075}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/Rosin12_Boolean_Excitability.pdf}, Abstract = {We demonstrate theoretically and experimentally that excitable systems can be built with autonomous Boolean networks. Their experimental implementation is realized with asynchronous logic gates on a reconfigurabe chip. When these excitable systems are assembled into time-delay networks, their dynamics display nanosecond time scale spike synchronization patterns that are controllable in period and phase. © Copyright EPLA, 2012.}, Doi = {10.1209/0295-5075/100/30003}, Key = {fds246374} } @article{fds246271, Author = {Bolduc, E and Leach, J and Gauthier, D and Boyd, RW}, Title = {The security of quantum key distribution using the orbital angular momentum states of light}, Journal = {Optics Infobase Conference Papers}, Year = {2012}, Month = {December}, ISSN = {2162-2701}, Abstract = {High-dimensional entanglement is a key resource for quantum cryptography. We experimentally realise the criterion for secure quantum key distribution when using photons entangled in the orbital angular momentum and angle degrees of freedom. © 2012 OSA.}, Key = {fds246271} } @article{fds246275, Author = {Christensen, BG and McCusker, KT and Gauthier, DJ and Kwiat, PG}, Title = {High-speed quantum key distribution using hyper-entangled photons}, Journal = {Optics Infobase Conference Papers}, Year = {2012}, Month = {December}, Abstract = {We discuss a quantum cryptography system using the timing and polarization degrees of freedom to produce a high bit rate for both technologically limited eavesdroppers and for any potential eavesdroppers. © 2012 OSA.}, Key = {fds246275} } @article{fds246276, Author = {Gauthier, DJ and Guilbert, H and Zhu, Y and Shi, M and McCusker, KT and Christensen, B and Kwiat, P and Brougham, T and Barnett, SM and Chandar, V}, Title = {Quantum key distribution using hyperentanglement}, Journal = {Optics Infobase Conference Papers}, Year = {2012}, Month = {December}, Abstract = {We describe our progress on achieving quantum key distribution with high photon efficiency and high rate using hyperentanglement. Our goal is encode 10 bits per photon and distribute a secure key at 1 Gbit/s. © 2012 OSA.}, Key = {fds246276} } @article{fds246279, Author = {Christensen, BG and McCusker, KT and Gauthier, DJ and Kwiat, PG}, Title = {High-speed quantum key distribution using hyper-entangled photons}, Journal = {Cleo: Applications and Technology, Cleo at 2012}, Pages = {JW4A.115}, Year = {2012}, Month = {December}, Abstract = {We discuss a quantum cryptography system using the timing and polarization degrees of freedom to produce a high bit rate for both technologically limited eavesdroppers and for any potential eavesdroppers. © OSA 2012.}, Key = {fds246279} } @article{fds246280, Author = {Christensen, BG and McCusker, KT and Gauthier, DJ and Kwiat, PG}, Title = {High-speed quantum key distribution using hyper-entangled photons}, Journal = {Cleo: Applications and Technology, Cleo at 2012}, Pages = {JW4A.115}, Year = {2012}, Month = {December}, Abstract = {We discuss a quantum cryptography system using the timing and polarization degrees of freedom to produce a high bit rate for both technologically limited eavesdroppers and for any potential eavesdroppers. © OSA 2012.}, Key = {fds246280} } @article{fds246372, Author = {Gauthier, DJ}, Title = {Comment on "Generalized grating equation for virtually imaged phased-array spectral dispersers".}, Journal = {Applied Optics}, Volume = {51}, Number = {34}, Pages = {8184-8186}, Year = {2012}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23207388}, Abstract = {I correct an error made by Vega et al. [Appl. Opt. 42, 4152 (2003)], who derived the spectral dispersion properties of a virtually imaged phased-array etalon using a ray-based, multibounce interference analysis. I demonstrate that the corrected dispersion law is in agreement with the results obtained by paraxial wave theory [Xiao et al., IEEE J. Quantum Electron.40, 420 (2004)].}, Doi = {10.1364/ao.51.008184}, Key = {fds246372} } @article{fds246373, Author = {Cohen, SD and Rontani, D and Gauthier, DJ}, Title = {Ultra-high-frequency piecewise-linear chaos using delayed feedback loops.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {22}, Number = {4}, Pages = {043112}, Year = {2012}, Month = {December}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23278047}, Abstract = {We report on an ultra-high-frequency (>1 GHz), piecewise-linear chaotic system designed from low-cost, commercially available electronic components. The system is composed of two electronic time-delayed feedback loops: A primary analog loop with a variable gain that produces multi-mode oscillations centered around 2 GHz and a secondary loop that switches the variable gain between two different values by means of a digital-like signal. We demonstrate experimentally and numerically that such an approach allows for the simultaneous generation of analog and digital chaos, where the digital chaos can be used to partition the system's attractor, forming the foundation for a symbolic dynamics with potential applications in noise-resilient communications and radar.}, Doi = {10.1063/1.4766593}, Key = {fds246373} } @article{fds246375, Author = {Hall, GM and Holder, EJ and Cohen, SD and Gauthier, DJ}, Title = {Low-cost chaotic radar design}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {8361}, Pages = {836112}, Publisher = {SPIE}, Year = {2012}, Month = {December}, url = {http://www.phy.duke.edu/research/photon/qelectron/pubs/SPIE8361_836112_2012.pdf}, Abstract = {An approach for creating a low-cost Chaos Pulsed-Doppler Radar is presented. The objective of this effort is to develop a practical realization of a Chaotic Radar with performance advantages over other approaches. Many groups have proposed that Chaotic Waveforms are an effective radar signal generator due to: the relatively low cost of producing complex wideband waveforms and the difficulty in detecting and spoofing inherently complex modulations. PRA and Duke University report on the development of a radar design that uses a novel high-speed chaotic waveform generator. Preliminary experimental results are presented that characterize the performance of a chaotic waveform generator. In addition, the radar architecture will be proposed, realistic radar design criterion will be set forth, and simulations of a complete radar will be used to compare the chaotic radar to more traditional radar approaches. © 2012 SPIE.}, Doi = {10.1117/12.918503}, Key = {fds246375} } @article{fds287611, Author = {Bolduc, E and Leach, J and Gauthier, D and Boyd, RW}, Title = {The secure information capacity of photons entangled in high dimensions}, Journal = {Frontiers in Optics, Fio 2012}, Year = {2012}, Month = {December}, Abstract = {We quantify precisely the maximum secure information capacity of photons entangled in high dimensions for entanglement in the orbital angular momentum and angular degrees of freedom. © 2012.}, Key = {fds287611} } @article{fds246359, Author = {Christensen, BG and McCusker, KT and Gauthier, DJ and Kwiat, PG}, Title = {High-speed quantum key distribution using hyper-entangled photons}, Journal = {2012 Conference on Lasers and Electro Optics, Cleo 2012}, Year = {2012}, Month = {December}, Abstract = {We discuss a quantum cryptography system using the timing and polarization degrees of freedom to produce a high bit rate for both technologically limited eavesdroppers and for any potential eavesdroppers. © 2012 OSA.}, Key = {fds246359} } @article{fds246277, Author = {Kim, J and Clark, R and Gauthier, D}, Title = {Low-noise frequency downconversion for long-distance distribution of entangled atomic qubits}, Journal = {2013 Ieee Photonics Society Summer Topical Meeting Series, Psstms 2013}, Pages = {183-184}, Publisher = {IEEE}, Year = {2013}, url = {http://www.phy.duke.edu/~qelectron/pubs/StipcevicSPIE2013.pdf}, Abstract = {Distribution of quantum resources such as entanglement over distances beyond a few fiber attenuation lengths requires realization of quantum repeaters that utilize entanglement swapping to extend the distance between the entangled qubit pairs [1]. A quantum repeater is a small quantum computer capable of generating entangled qubit pairs with its neighboring repeaters and storing them in stable quantum memories. Once the entangled pairs are generated, it will perform Bell basis measurements, classical communication with appropriate repeaters, and single qubit gates necessary for entanglement swapping. For high fidelity operation, it might perform local operations and classical communications (LOCC) such as entanglement distillation [2] and/or quantum error correction [3,4]. Generation of remote entangled ion pairs mediated by photonic qubits has been demonstrated [5] but their reach is limited since the photons used in the experiment are in the UV part of the spectrum. Coherent conversion of the photons emitted by Yb ion at 369.5nm to a photon at 1310 nm would enable entanglement generation over long distances [6]. © 2013 IEEE.}, Doi = {10.1109/PHOSST.2013.6614563}, Key = {fds246277} } @article{fds246238, Author = {Schmittberger, BL and Greenberg, JA and Gauthier, DJ}, Title = {Ultra-low-threshold optical pattern formation in a cold atomic vapor}, Journal = {2013 Conference on Lasers and Electro Optics Europe and International Quantum Electronics Conference, Cleo/Europe Iqec 2013}, Year = {2013}, Month = {January}, url = {http://dx.doi.org/10.1109/CLEOE-IQEC.2013.6801811}, Abstract = {The study of pattern formation in nonlinear optical systems has provided new insight into a wide variety of phenomena such as fundamental many-body physics, optical soliton formation, nonlinear lensing, and transverse optical pattern formation [1]. The generation of transverse optical patterns in cold atomic vapors is of particular interest in condensed matter physics because the resulting multimode optical fields act back on the atoms and create self-organized density gratings of atoms [2]. The formation of these density gratings enhances the nonlinear response of the system, which leads to lower threshold input powers required for pattern formation. Achieving sufficiently low threshold powers would make optical pattern formation in cold atomic systems relevant to creating quantum networks and performing weak measurements [3]. © 2013 IEEE.}, Doi = {10.1109/CLEOE-IQEC.2013.6801811}, Key = {fds246238} } @article{fds246261, Author = {Guilbert, H and Wong, YP and Gauthier, DJ}, Title = {Observation of elliptical patterns in type I spontaneous parametric down conversion}, Journal = {Optics Infobase Conference Papers}, Year = {2013}, Month = {January}, Abstract = {We measure the spatial profile of down-converted light from Type-I SPDC in BBO and BiBO crystals. We find BiBO (BBO) produces elliptical (circular) transverse patterns because the generated light experiences an angle-dependent (-independent) refractive index. © OSA 2013.}, Key = {fds246261} } @article{fds246291, Author = {Zheng, H and Gauthier, DJ and Baranger, HU}, Title = {Decoy-state quantum key distribution with nonclassical light generated in a one-dimensional waveguide.}, Journal = {Optics Letters}, Volume = {38}, Number = {5}, Pages = {622-624}, Year = {2013}, Month = {March}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23455244}, Abstract = {We investigate a decoy-state quantum key distribution (QKD) scheme with a sub-Poissonian single-photon source, which is generated on demand by scattering a coherent state off a two-level system in a one-dimensional waveguide. We show that, compared to coherent state decoy-state QKD, there is a two-fold increase of the key generation rate. Furthermore, the performance is shown to be robust against both parameter variations and loss effects of the system.}, Doi = {10.1364/ol.38.000622}, Key = {fds246291} } @article{fds246292, Author = {Rosin, DP and Rontani, D and Gauthier, DJ and Schöll, E}, Title = {Control of synchronization patterns in neural-like Boolean networks.}, Journal = {Physical Review Letters}, Volume = {110}, Number = {10}, Pages = {104102}, Year = {2013}, Month = {March}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23521258}, Abstract = {We study experimentally the synchronization patterns in time-delayed directed Boolean networks of excitable systems. We observe a transition in the network dynamics when the refractory time of the individual systems is adjusted. When the refractory time is on the same order of magnitude as the mean link time delays or the heterogeneities of the link time delays, cluster synchronization patterns change, or are suppressed entirely, respectively. We also show that these transitions occur when we change the properties of only a small number of driver nodes identified by their larger in degree; hence, the synchronization patterns can be controlled locally by these nodes. Our findings have implications for synchronization in biological neural networks.}, Doi = {10.1103/physrevlett.110.104102}, Key = {fds246292} } @article{fds246289, Author = {Zhu, Y and Kim, J and Gauthier, DJ}, Title = {Aberration-corrected quantum temporal imaging system}, Journal = {Physical Review A}, Volume = {87}, Number = {4}, Pages = {043808}, Publisher = {American Physical Society (APS)}, Year = {2013}, Month = {April}, ISSN = {1050-2947}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000317193600009&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Doi = {10.1103/PhysRevA.87.043808}, Key = {fds246289} } @article{fds246290, Author = {Rosin, DP and Rontani, D and Gauthier, DJ}, Title = {Ultrafast physical generation of random numbers using hybrid Boolean networks.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {87}, Number = {4}, Pages = {040902}, Year = {2013}, Month = {April}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23679363}, Abstract = {We describe a high-speed physical random number generator based on a hybrid Boolean network with autonomous and clocked logic gates, realized on a reconfigurable chip. The autonomous logic gates are arranged in a bidirectional ring topology and generate broadband chaos. The clocked logic gates receive input from the autonomous logic gates so that random numbers are generated physically that pass standard randomness tests without further postprocessing. The large number of logic gates on reconfigurable chips allows for parallel generation of random numbers, as demonstrated by our implementation of 128 physical random number generators that achieve a real-time bit rate of 12.8Gbits/s.}, Doi = {10.1103/physreve.87.040902}, Key = {fds246290} } @article{fds246284, Author = {Rosin, DP and Rontani, D and Gauthier, DJ}, Title = {Erratum: Ultrafast physical generation of random numbers using hybrid Boolean networks (Physical Review E - Statistical, Nonlinear, and Soft Matter Physics (2013) 87 (040902))}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {87}, Number = {5}, Publisher = {American Physical Society (APS)}, Year = {2013}, Month = {May}, ISSN = {1539-3755}, url = {http://dx.doi.org/10.1103/PhysRevE.87.059902}, Doi = {10.1103/PhysRevE.87.059902}, Key = {fds246284} } @article{fds246288, Author = {Brougham, T and Barnett, SM and McCusker, KT and Kwiat, PG and Gauthier, DJ}, Title = {Security of high-dimensional quantum key distribution protocols using Franson interferometers}, Journal = {Journal of Physics B: Atomic, Molecular and Optical Physics}, Volume = {46}, Number = {10}, Pages = {104010-104010}, Publisher = {IOP Publishing}, Year = {2013}, Month = {May}, ISSN = {0953-4075}, url = {http://www.phy.duke.edu/~qelectron/pubs/FransonQKDn3-2013.pdf}, Abstract = {Franson interferometers are increasingly being proposed as a means of securing high-dimensional energy-time entanglement-based quantum key distribution (QKD) systems. Heuristic arguments have been proposed that purport to demonstrate the security of these schemes. We show, however, that such systems are vulnerable to attacks that localize the photons to several temporally separate locations. This demonstrates that a single pair of Franson interferometers is not a practical approach to securing high-dimensional energy-time entanglement-based QKD. This observation leads us to investigate the security of modified Franson-based-protocols, where Alice and Bob have two or more Franson interferometers. We show that such setups can improve the sensitivity against attacks that localize the photons to multiple temporal locations. While our results do not constitute a full security proof, they do show that a single pair of Franson interferometers is not secure and that multiple such interferometers could be a promising candidate for experimentally realizable high-dimensional QKD. © 2013 IOP Publishing Ltd.}, Doi = {10.1088/0953-4075/46/10/104010}, Key = {fds246288} } @article{fds246285, Author = {Jackson, AD and Huang, D and Gauthier, DJ and Venakides, S}, Title = {Destructive impact of imperfect beam collimation in extraordinary optical transmission.}, Journal = {Journal of the Optical Society of America A}, Volume = {30}, Number = {6}, Pages = {1281-1290}, Year = {2013}, Month = {June}, ISSN = {1084-7529}, url = {http://www.phy.duke.edu/~qelectron/pubs/JOSAA30_1281_2013.pdf}, Abstract = {We investigate the difference between analytic predictions, numerical simulations, and experiments measuring the transmission of energy through subwavelength, periodically arranged holes in a metal film. At normal incidence, theory predicts a sharp transmission minimum when the wavelength is equal to the periodicity, and sharp transmission maxima at one or more nearby wavelengths. In experiments, the sharpest maximum from the theory is not observed, while the others appear less sharp. In numerical simulations using commercial electromagnetic field solvers, we find that the sharpest maximum appears and approaches our predictions as the computational resources are increased. To determine possible origins of the destruction of the sharp maximum, we incorporate additional features in our model. Incorporating imperfect conductivity and imperfect periodicity in our model leaves the sharp maximum intact. Imperfect collimation, on the other hand, incorporated into the model causes the destruction of the sharp maximum as happens in experiments. We provide analytic support through an asymptotic calculation for both the existence of the sharp maximum and the destructive impact of imperfect collimation.}, Doi = {10.1364/josaa.30.001281}, Key = {fds246285} } @article{fds246286, Author = {Vornehm, JE and Schweinsberg, A and Shi, Z and Gauthier, DJ and Boyd, RW}, Title = {Phase locking of multiple optical fiber channels for a slow-light-enabled laser radar system.}, Journal = {Optics Express}, Volume = {21}, Number = {11}, Pages = {13094-13104}, Year = {2013}, Month = {June}, ISSN = {1094-4087}, url = {http://www.phy.duke.edu/~qelectron/pubs/OptExpress21_13094_2013.pdf}, Abstract = {Phase control is crucial to the operation of coherent beam combining systems, whether for laser radar or high-power beam combining. We have recently demonstrated a design for a multi-aperture, coherently combined, synchronized- and phased-array slow light laser radar (SLIDAR) that is capable of scanning in two dimensions with dynamic group delay compensation. Here we describe in detail the optical phase locking system used in the design. The phase locking system achieves an estimated Strehl ratio of 0.8, and signals from multiple emitting apertures are phase locked simultaneously to within π/5 radians (1/10 wave) after propagation through 2.2 km of single-mode fiber per channel. Phase locking performance is maintained even as two independent slow light mechanisms are utilized simultaneously.}, Doi = {10.1364/oe.21.013094}, Key = {fds246286} } @article{fds246287, Author = {Rosin, DP and Rontani, D and Gauthier, DJ and Schöll, E}, Title = {Experiments on autonomous Boolean networks.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {23}, Number = {2}, Pages = {025102}, Year = {2013}, Month = {June}, url = {http://www.ncbi.nlm.nih.gov/pubmed/23822500}, Abstract = {We realize autonomous Boolean networks by using logic gates in their autonomous mode of operation on a field-programmable gate array. This allows us to implement time-continuous systems with complex dynamical behaviors that can be conveniently interconnected into large-scale networks with flexible topologies that consist of time-delay links and a large number of nodes. We demonstrate how we realize networks with periodic, chaotic, and excitable dynamics and study their properties. Field-programmable gate arrays define a new experimental paradigm that holds great potential to test a large body of theoretical results on the dynamics of complex networks, which has been beyond reach of traditional experimental approaches.}, Doi = {10.1063/1.4807481}, Key = {fds246287} } @article{fds246371, Author = {Stipčević, M and Gauthier, DJ}, Title = {Precise Monte Carlo simulation of single-photon detectors}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {8727}, Pages = {87270K}, Publisher = {SPIE}, Editor = {M.A. Itzler and J.C. Campbell}, Year = {2013}, Month = {August}, url = {http://www.phy.duke.edu/~qelectron/pubs/StipcevicSPIE2013.pdf}, Abstract = {We demonstrate the importance and utility of Monte Carlo simulation of single-photon detectors. Devising an optimal simulation is strongly influenced by the particular application because of the complexity of modern, avalanche-diodebased single-photon detectors. Using a simple yet very demanding example of random number generation via detection of Poissonian photons exiting a beam splitter, we present a Monte Carlo simulation that faithfully reproduces the serial autocorrelation of random bits as a function of detection frequency over four orders of magnitude of the incident photon flux. We conjecture that this simulation approach can be easily modified for use in many other applications. © 2013 SPIE.}, Doi = {10.1117/12.2021577}, Key = {fds246371} } @article{fds220520, Author = {H. Zheng and D.J. Gauthier and H.U. Baranger}, Title = {Waveguide-QED-Based Photonic Quantum Computation}, Journal = {Phys. Rev. Lett.}, Volume = {111}, Pages = {090502}, Year = {2013}, Month = {August}, url = {http://www.phy.duke.edu/~qelectron/pubs/PRL111_090502_2013.pdf}, Key = {fds220520} } @article{fds303664, Author = {Zheng, H and Gauthier, DJ and Baranger, HU}, Title = {Waveguide-QED-Based Photonic Quantum Computation}, Journal = {Physical Review Letters}, Volume = {111}, Number = {9}, Pages = {090502}, Publisher = {American Physical Society (APS)}, Year = {2013}, Month = {August}, url = {http://arxiv.org/abs/1211.1711v3}, Abstract = {We propose a new scheme for quantum computation using flying qubits--propagating photons in a one-dimensional waveguide interacting with matter qubits. Photon-photon interactions are mediated by the coupling to a four-level system, based on which photon-photon π-phase gates (CONTROLLED-NOT) can be implemented for universal quantum computation. We show that high gate fidelity is possible, given recent dramatic experimental progress in superconducting circuits and photonic-crystal waveguides. The proposed system can be an important building block for future on-chip quantum networks.}, Doi = {10.1103/physrevlett.111.090502}, Key = {fds303664} } @article{fds246281, Author = {Cohen, SD and Aragoneses, A and Rontani, D and Torrent, MC and Masoller, C and Gauthier, DJ}, Title = {Multidimensional subwavelength position sensing using a semiconductor laser with optical feedback.}, Journal = {Optics Letters}, Volume = {38}, Number = {21}, Pages = {4331-4334}, Year = {2013}, Month = {November}, ISSN = {0146-9592}, url = {http://www.phy.duke.edu/~qelectron/pubs/OptLett38_4331_2013.pdf}, Abstract = {We demonstrate experimentally how to harness quasi-periodic dynamics in a semiconductor laser with dual optical feedback for measuring subwavelength changes in each arm of the cavity simultaneously. We exploit the multifrequency spectrum of quasi-periodic dynamics and show that independent frequency shifts are mapped uniquely to two-dimensional displacements of the arms in the external cavity. Considering a laser diode operating at telecommunication wavelength λ≈1550 nm, we achieve an average nanoscale resolution of approximately 9.8 nm (~λ/160).}, Doi = {10.1364/ol.38.004331}, Key = {fds246281} } @article{fds246282, Author = {Cavalcante, HLDDS and Oriá, M and Sornette, D and Ott, E and Gauthier, DJ}, Title = {Predictability and suppression of extreme events in a chaotic system.}, Journal = {Physical Review Letters}, Volume = {111}, Number = {19}, Pages = {198701}, Year = {2013}, Month = {November}, ISSN = {0031-9007}, url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000326531300013&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=47d3190e77e5a3a53558812f597b0b92}, Abstract = {In many complex systems, large events are believed to follow power-law, scale-free probability distributions so that the extreme, catastrophic events are unpredictable. Here, we study coupled chaotic oscillators that display extreme events. The mechanism responsible for the rare, largest events makes them distinct, and their distribution deviates from a power law. On the basis of this mechanism identification, we show that it is possible to forecast in real time an impending extreme event. Once forecasted, we also show that extreme events can be suppressed by applying tiny perturbations to the system.}, Doi = {10.1103/physrevlett.111.198701}, Key = {fds246282} } @article{fds220521, Author = {H. L. D. de S. Cavalcante and M. Oriá and D. Sornette and E. Ott and and D. J. Gauthier}, Title = {Precidtability and suppression of extreme events in a chaotic system}, Journal = {Phys. Rev. Lett.}, Volume = {111}, Pages = {198701}, Year = {2013}, Month = {November}, url = {http://www.phy.duke.edu/~qelectron/pubs/PRL111_198701_2013.pdf}, Key = {fds220521} } @article{fds318444, Author = {Gauthier, DJ and Wildfeuer, CF and Guilbert, H and Stipčević, M and Christensen, B and Kumor, D and Kwiat, P and McCusker, K and Brougham, T and Barnett, SM}, Title = {Quantum key distribution using hyperentangled time-bin states}, Journal = {Optics Infobase Conference Papers}, Year = {2013}, Month = {December}, Abstract = {We describe our progress on achieving quantum key distribution with high photon efficiency and high rate using hyperentanglement. Methods of securing time-bin states and classical error correction appropriate for our high-dimension protocols will be discussed. © OSA 2013.}, Key = {fds318444} } @article{fds246235, Author = {Christensen, B and Kumor, D and McCusker, K and Chandar, V and Gauthier, D and Kwiat, P}, Title = {Information reconciliation in higher-dimensional quantum cryptography}, Journal = {Optics Infobase Conference Papers}, Year = {2013}, Month = {December}, ISSN = {2162-2701}, Abstract = {We report on a high-speed quantum cryptography system that utilizes simultaneous entanglement in polarization and time-bins. We also show a practical implementation of information reconciliation using concatenated low density parity check codes. © 2013 Optical Society of America.}, Key = {fds246235} } @article{fds246263, Author = {Schmittberger, BL and Greenberg, JA and Gauthier, DJ}, Title = {Ultra-low-threshold optical pattern formation in a cold atomic vapor}, Journal = {Optics Infobase Conference Papers}, Publisher = {IEEE}, Year = {2013}, Month = {December}, url = {http://dx.doi.org/10.1109/cleoe-iqec.2013.6801811}, Doi = {10.1109/cleoe-iqec.2013.6801811}, Key = {fds246263} } @article{fds246264, Author = {Gauthier, DJ and Wildfeuer, CF and Guilbert, H and Stipčević, M and Christensen, B and Kumor, D and Kwiat, P and McCusker, K and Brougham, T and Barnett, SM}, Title = {Quantum key distribution using hyperentangled time-bin states}, Journal = {Optics Infobase Conference Papers}, Editor = {N. Bigelow and J. Eberly}, Year = {2013}, Month = {December}, url = {http://www.phy.duke.edu/~qelectron/pubs/GauthierQIMAug23-2013-Paper.pdf}, Abstract = {We describe our progress on achieving quantum key distribution with high photon efficiency and high rate using hyperentanglement. Methods of securing time-bin states and classical error correction appropriate for our high-dimension protocols will be discussed. © OSA 2013.}, Key = {fds246264} } @article{fds246265, Author = {Gauthier, DJ and Schmittberger, BL and Greenberg, JA}, Title = {Transverse optical patterns for low-light-level optical switching}, Journal = {Optics Infobase Conference Papers}, Year = {2013}, Month = {December}, Abstract = {We demonstrate that Sisyphus cooling of atoms leads to a new source of nonlinear optical interaction that drastically increases the interaction strength. This increased coupling leads to low-threshold pattern formation, with applications in single-photon switching. © OSA 2013.}, Key = {fds246265} } @article{fds246231, Author = {Sorrentino, T and Aragoneses, A and Perrone, S and Gauthier, DJ and Torrent, MC and Masoller, C}, Title = {Experimental study of the complex dynamics of semiconductor lasers with feedback via symbolic time-series analysis}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {9134}, Publisher = {SPIE}, Year = {2014}, Month = {January}, ISSN = {0277-786X}, url = {http://dx.doi.org/10.1117/12.2052322}, Abstract = {We investigate the symbolic dynamics of an excitable optical system under periodic forcing. Particularly, we consider the low-frequency fluctuation (LFF) dynamics of a semiconductor laser with periodically-modulated injection current and optical feedback. We use a method of symbolic time-series analysis that allows us to unveil serial correlations in the sequence of intensity dropouts. By transforming the sequence of inter-dropout intervals into a sequence of ordinal patterns and analyzing the statistics of the patterns, we uncover correlations among several consecutive dropouts and we identify definite changes in the dynamics as the modulation amplitude increases. We confirm the robustness of the observations by conducting the experiments with two different lasers under different feedback conditions. The results are also shown to be robust to variations of the threshold used for detecting the dropouts. Simulations of the Lang-Kobayashi (LK) model, including spontaneous emission noise, are found to be in good qualitative agreement with the observations, providing an interpretation of the correlations present in the dropout sequence as due to the interplay of the underlying attractor topology, the periodic forcing, and the noise that sustains the dropout events. © 2014 SPIE.}, Doi = {10.1117/12.2052322}, Key = {fds246231} } @article{fds246239, Author = {Christensen, BG and McCusker, KT and Gauthier, DJ and Kumor, DR and Chandar, V and Kwiat, PG}, Title = {Higher-dimensional quantum cryptography}, Journal = {Optics Infobase Conference Papers}, Year = {2014}, Month = {January}, Abstract = {We report on a high-speed quantum cryptography system with simultaneous entanglement in polarization and "time-bins". We use multiple degrees of freedom and multiple spots on the downconversion cone to achieve 14 Mbits/s of secure key.© OSA 2014.}, Key = {fds246239} } @article{fds246213, Author = {Gauthier, DJ and Schmittberger, BL}, Title = {Observation of ultra-low-light-level self-organized pattern formation in driven cold atoms,}, Year = {2014}, Month = {January}, url = {http://www.pqeconference.com/pqe2014/abstractd/61p.pdf}, Key = {fds246213} } @article{fds246273, Author = {Aragoneses, A and Sorrentino, T and Perrone, S and Gauthier, DJ and Torrent, MC and Masoller, C}, Title = {Experimental and numerical study of the symbolic dynamics of a modulated external-cavity semiconductor laser.}, Journal = {Optics Express}, Volume = {22}, Number = {4}, Pages = {4705-4713}, Year = {2014}, Month = {February}, url = {http://dx.doi.org/10.1364/oe.22.004705}, Abstract = {We study the symbolic dynamics of a stochastic excitable optical system with periodic forcing. Specifically, we consider a directly modulated semiconductor laser with optical feedback in the low frequency fluctuations (LFF) regime. We use a method of symbolic time-series analysis that allows us to uncover serial correlations in the sequence of intensity dropouts. By transforming the sequence of inter-dropout intervals into a sequence of symbolic patterns and analyzing the statistics of the patterns, we unveil correlations among several consecutive dropouts and we identify clear changes in the dynamics as the modulation amplitude increases. To confirm the robustness of the observations, the experiments were performed using two lasers under different feedback conditions. Simulations of the Lang-Kobayashi (LK) model, including spontaneous emission noise, are found to be in good agreement with the observations, providing an interpretation of the correlations present in the dropout sequence as due to the interplay of the underlying attractor topology, the external forcing, and the noise that sustains the dropout events.}, Doi = {10.1364/oe.22.004705}, Key = {fds246273} } @article{fds246240, Author = {Rosin, DP and Rontani, D and Gauthier, DJ}, Title = {Synchronization of coupled Boolean phase oscillators.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {89}, Number = {4}, Pages = {042907}, Year = {2014}, Month = {April}, ISSN = {1539-3755}, url = {http://dx.doi.org/10.1103/physreve.89.042907}, Abstract = {We design, characterize, and couple Boolean phase oscillators that include state-dependent feedback delay. The state-dependent delay allows us to realize an adjustable coupling strength, even though only Boolean signals are exchanged. Specifically, increasing the coupling strength via the range of state-dependent delay leads to larger locking ranges in uni- and bidirectional coupling of oscillators in both experiment and numerical simulation with a piecewise switching model. In the unidirectional coupling scheme, we unveil asymmetric triangular-shaped locking regions (Arnold tongues) that appear at multiples of the natural frequency of the oscillators. This extends observations of a single locking region reported in previous studies. In the bidirectional coupling scheme, we map out a symmetric locking region in the parameter space of frequency detuning and coupling strength. Because of the large scalability of our setup, our observations constitute a first step towards realizing large-scale networks of coupled oscillators to address fundamental questions on the dynamical properties of networks in a new experimental setting.}, Doi = {10.1103/physreve.89.042907}, Key = {fds246240} } @article{fds246214, Author = {Gauthier, DJ}, Title = {Steady-state, cavity-less, multimode superradiance}, Year = {2014}, Month = {May}, Key = {fds246214} } @article{fds246232, Author = {Zhu, Y and Greenberg, JA and Husein, NA and Gauthier, DJ}, Title = {Giant all-optical tunable group velocity dispersion in an optical fiber.}, Journal = {Optics Express}, Volume = {22}, Number = {12}, Pages = {14382-14391}, Year = {2014}, Month = {June}, url = {http://dx.doi.org/10.1364/oe.22.014382}, Abstract = {We realize a strongly dispersive material with large tunable group velocity dispersion (GVD) in a commercially-available photonic crystal fiber. Specifically, we pump the fiber with a two-frequency pump field that induces an absorbing resonance adjacent to an amplifying resonance via the stimulated Brillouin processes. We demonstrate all-optical control of the GVD by measuring the linear frequency chirp impressed on a 28-nanosecond-duration optical pulse by the medium and find that it is tunable over the range ± 7.8 ns(2)/m. The maximum observed value of the GVD is 10(9) times larger than that in a typical single-mode silica optical fiber. Our observations are in good agreement with a theoretical model of the process.}, Doi = {10.1364/oe.22.014382}, Key = {fds246232} } @article{fds246236, Author = {Lin, Y and Ramirez-Giraldo, JC and Gauthier, DJ and Stierstorfer, K and Samei, E}, Title = {An angle-dependent estimation of CT x-ray spectrum from rotational transmission measurements.}, Journal = {Med Phys}, Volume = {41}, Number = {6}, Pages = {062104}, Year = {2014}, Month = {June}, ISSN = {0094-2405}, url = {http://dx.doi.org/10.1118/1.4876380}, Abstract = {PURPOSE: Computed tomography (CT) performance as well as dose and image quality is directly affected by the x-ray spectrum. However, the current assessment approaches of the CT x-ray spectrum require costly measurement equipment and complicated operational procedures, and are often limited to the spectrum corresponding to the center of rotation. In order to address these limitations, the authors propose an angle-dependent estimation technique, where the incident spectra across a wide range of angular trajectories can be estimated accurately with only a single phantom and a single axial scan in the absence of the knowledge of the bowtie filter. METHODS: The proposed technique uses a uniform cylindrical phantom, made of ultra-high-molecular-weight polyethylene and positioned in an off-centered geometry. The projection data acquired with an axial scan have a twofold purpose. First, they serve as a reflection of the transmission measurements across different angular trajectories. Second, they are used to reconstruct the cross sectional image of the phantom, which is then utilized to compute the intersection length of each transmission measurement. With each CT detector element recording a range of transmission measurements for a single angular trajectory, the spectrum is estimated for that trajectory. A data conditioning procedure is used to combine information from hundreds of collected transmission measurements to accelerate the estimation speed, to reduce noise, and to improve estimation stability. The proposed spectral estimation technique was validated experimentally using a clinical scanner (Somatom Definition Flash, Siemens Healthcare, Germany) with spectra provided by the manufacturer serving as the comparison standard. Results obtained with the proposed technique were compared against those obtained from a second conventional transmission measurement technique with two materials (i.e., Cu and Al). After validation, the proposed technique was applied to measure spectra from the clinical system across a range of angular trajectories [-15°, 15°] and spectrum settings (80, 100, 120, 140 kVp). RESULTS: At 140 kVp, the proposed technique was comparable to the conventional technique in terms of the mean energy difference (MED, -0.29 keV) and the normalized root mean square difference (NRMSD, 0.84%) from the comparison standard compared to 0.64 keV and 1.56%, respectively, with the conventional technique. The average absolute MEDs and NRMSDs across kVp settings and angular trajectories were less than 0.61 keV and 3.41%, respectively, which indicates a high level of estimation accuracy and stability. CONCLUSIONS: An angle-dependent estimation technique of CT x-ray spectra from rotational transmission measurements was proposed. Compared with the conventional technique, the proposed method simplifies the measurement procedures and enables incident spectral estimation for a wide range of angular trajectories. The proposed technique is suitable for rigorous research objectives as well as routine clinical quality control procedures.}, Doi = {10.1118/1.4876380}, Key = {fds246236} } @article{fds246215, Author = {Gauthier, DJ and Schmittberger, BL}, Title = {Optical Pattern Formation in Spatially Bunched Atoms: A Self-Consistent Model and Experiment}, Year = {2014}, Month = {June}, url = {http://meetings.aps.org/Meeting/DAMOP14/Session/N6.1}, Key = {fds246215} } @article{fds246216, Author = {Gauthier, DJ and Rosin, DP and Soriano, MC and Fischer, I and Haynes, ND}, Title = {Reservoir computing with a single autonomous Boolean node using time-delay feedback}, Year = {2014}, Month = {June}, Key = {fds246216} } @article{fds246217, Author = {Gauthier, DJ and Rosin, DP and Rontani, D and Haynes, ND}, Title = {Dynamics and control of time-delay Boolean networks}, Year = {2014}, Month = {June}, Key = {fds246217} } @article{fds246218, Author = {Gauthier, DJ and Schmittberger, BL}, Title = {Superradiance in Driven Ultra-Cold Atoms}, Year = {2014}, Month = {July}, Key = {fds246218} } @article{fds246229, Author = {Schmittberger, BL and Gauthier, DJ}, Title = {Enhancing light-atom interactions via atomic bunching}, Journal = {Physical Review A}, Volume = {90}, Number = {1}, Publisher = {American Physical Society (APS)}, Year = {2014}, Month = {July}, ISSN = {1050-2947}, url = {http://hdl.handle.net/10161/9272 Duke open access}, Abstract = {There is a broad interest in enhancing the strength of light-atom interactions to the point where injecting a single photon induces a nonlinear material response. Here we show theoretically that sub-Doppler-cooled two-level atoms that are spatially organized by weak optical fields give rise to a nonlinear material response that is greatly enhanced beyond that attainable in a homogeneous gas. Specifically, in the regime where the intensity of the applied optical fields is much less than the off-resonance saturation intensity, we show that the third-order nonlinear susceptibility scales inversely with atomic temperature and, due to this scaling, can be two orders of magnitude larger than that of a homogeneous gas for typical experimental parameters. As a result, we predict that spatially bunched two-level atoms can exhibit single-photon nonlinearities. Our model is valid for all regimes of atomic bunching and simultaneously accounts for the backaction of the atoms on the optical fields. Our results agree with previous theoretical and experimental results for light-atom interactions that have considered only limited regimes of atomic bunching. For lattice beams tuned to the low-frequency side of the atomic transition, we find that the nonlinearity transitions from a self-focusing type to a self-defocusing type at a critical intensity. We also show that higher than third-order nonlinear optical susceptibilities are significant in the regime where the dipole potential energy is on the order of the atomic thermal energy. We therefore find that it is crucial to retain high-order nonlinearities to accurately predict interactions of laser fields with spatially organized ultracold atoms. The model presented here is a foundation for modeling low-light-level nonlinear optical processes for ultracold atoms in optical lattices. © 2014 American Physical Society.}, Doi = {10.1103/PhysRevA.90.013813}, Key = {fds246229} } @article{fds325801, Author = {Mirhosseini, M and Magaña-Loaiza, OS and O'Sullivan, MN and Rodenburg, B and Shi, Z and Malik, M and Lavery, MPJ and Padgett, MJ and Gauthier, DJ and Boyd, RW}, Title = {Quantum information with structured light}, Journal = {Optics Infobase Conference Papers}, Volume = {Part F39-LS 2016}, Publisher = {OSA}, Year = {2014}, Month = {July}, ISBN = {9781943580194}, url = {http://dx.doi.org/10.1364/LS.2016.LTu1E.3}, Abstract = {© OSA 2016. We investigate structured photons as carriers of quantum information. We describe our implementation of quantum cryptography with orbital angular momentum, and present our results on efficient implementation of quantum state tomography for structured light fields.}, Doi = {10.1364/LS.2016.LTu1E.3}, Key = {fds325801} } @article{fds246219, Author = {Gauthier, DJ and Haynes, N and Rontani, D and Rosin, DP}, Title = {Autonomous Boolean networks for experimental network science and chimera states}, Year = {2014}, Month = {August}, Key = {fds246219} } @article{fds246228, Author = {Rosin, DP and Rontani, D and Haynes, ND and Schöll, E and Gauthier, DJ}, Title = {Transient scaling and resurgence of chimera states in networks of Boolean phase oscillators.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {90}, Number = {3}, Pages = {030902}, Year = {2014}, Month = {September}, ISSN = {1539-3755}, url = {http://hdl.handle.net/10161/9271 Duke open access}, Abstract = {We study networks of nonlocally coupled electronic oscillators that can be described approximately by a Kuramoto-like model. The experimental networks show long complex transients from random initial conditions on the route to network synchronization. The transients display complex behaviors, including resurgence of chimera states, which are network dynamics where order and disorder coexists. The spatial domain of the chimera state moves around the network and alternates with desynchronized dynamics. The fast time scale of our oscillators (on the order of 100ns) allows us to study the scaling of the transient time of large networks of more than a hundred nodes, which has not yet been confirmed previously in an experiment and could potentially be important in many natural networks. We find that the average transient time increases exponentially with the network size and can be modeled as a Poisson process in experiment and simulation. This exponential scaling is a result of a synchronization rate that follows a power law of the phase-space volume.}, Doi = {10.1103/physreve.90.030902}, Key = {fds246228} } @article{fds246226, Author = {Mirhosseini, M and Magana-Loaiza, OS and O'Sullivan, MN and Rodenburg, B and Malik, M and Lavery, MPJ and Padgett, MJ and Gauthier, DJ and Boyd, RW}, Title = {High-dimensional quantum key distribution with photonic orbital angular momentum}, Journal = {Frontiers in Optics, Fio 2014}, Year = {2014}, Month = {October}, ISBN = {1557522863}, Abstract = {© 2014 Optical Society of America. We experimentally demonstrate a quantum cryptography system based on photonic orbital angular momentum. The system achieves a channel capacity of 2.1 bits per sifted photon through the use of a 7-dimensional alphabet for encoding information.}, Key = {fds246226} } @article{fds246204, Author = {Guilbert, HE and Wong, YP and Gauthier, DJ}, Title = {Observation of elliptical rings in type-I spontaneous parametric downconversion}, Journal = {Journal of the Optical Society of America B}, Volume = {32}, Number = {10}, Pages = {2096-2103}, Publisher = {The Optical Society}, Year = {2015}, Month = {January}, ISSN = {0740-3224}, url = {http://dx.doi.org/10.1364/JOSAB.32.002096}, Abstract = {© 2015 Optical Society of America. We investigate the transverse spatial profile of downconverted light produced by noncollinear, degenerate, type-I spontaneous parametric downconversion in two types of nonlinear crystals. We find that the pattern produced by one crystal, beta barium borate (BBO), produces a circular downconversion pattern while the other crystal, bismuth triborate (BiBO), produces an elliptical pattern. We show this difference is due to the angle-independent refractive index experienced by the daughter photons in BBO, while they experience an angle-dependent refractive index in BiBO. We image the transverse spatial profile of the generated light to determine the eccentricity produced by each crystal and develop a model to explain our observation. Among other things, this model predicts that there is a wavelength for which the eccentricity from BiBO is nearly zero. Finally, we discuss how the elliptical ring pattern produced in BiBO potentially affects polarization entanglement for experimental setups that collect biphotons around the entire downconversion ring. We show that the quality of polarization entanglement as measured by the overlap integral of the spectrum of the two rings can remain high (>99.4%) around the entire ring at the expense of decreased biphoton rate.}, Doi = {10.1364/JOSAB.32.002096}, Key = {fds246204} } @article{fds246208, Author = {Baron, A and Larouche, S and Gauthier, DJ and Smith, DR}, Title = {Scaling of the nonlinear response of metal/dielectric plasmonic waveguides}, Journal = {Cleo: Qels Fundamental Science, Cleo Qels 2015}, Pages = {1551p}, Publisher = {OSA}, Year = {2015}, Month = {January}, ISBN = {9781557529688}, url = {http://dx.doi.org/10.1364/CLEO_QELS.2015.FM3E.7}, Abstract = {The scaling of the nonlinear response of a single-interface plasmonic waveguide is studied, where both the metal and dielectric display nonlinearity. We introduce a figure-of-merit that guides metal/dielectric nanophotonic device design for specific applications. © OSA 2015.}, Doi = {10.1364/CLEO_QELS.2015.FM3E.7}, Key = {fds246208} } @article{fds246211, Author = {Baron, A and Larouche, S and Gauthier, DJ and Smith, DR}, Title = {Scaling of the nonlinear response of the surface plasmon polariton at a metal/dielectric interface}, Journal = {Journal of the Optical Society of America B}, Volume = {32}, Number = {1}, Pages = {9-14}, Publisher = {The Optical Society}, Year = {2015}, Month = {January}, ISSN = {0740-3224}, url = {http://dx.doi.org/10.1364/JOSAB.32.000009}, Abstract = {© 2015 Optical Society of America. Plasmonic systems involve interfaces containing metal and dielectric materials. In an effort to investigate the scaling of the nonlinear response of the surface plasmon polariton at a metal/dielectric interface, where the metal and dielectric present optical nonlinearity, we introduce a figure-of-merit that quantifies the contribution of the metal and the dielectric to the nonlinear response in this specific situation. In the case of self-action of the surface plasmon polariton for the gold/dielectric interface, we predict that the dielectric nonlinear response is dominant for strongly nonlinear dielectrics such as polydiacetylenes, chalcogenide glasses, or even semiconductors. The gold nonlinear response is dominant only in cases involving weakly nonlinear dielectrics such as silicon dioxide or aluminum oxide. We verify the relevance of the metric by investigating the process of optical switching via the third-order nonlinear response and discuss which gold/dielectric combinations have better switching behaviors.}, Doi = {10.1364/JOSAB.32.000009}, Key = {fds246211} } @article{fds246227, Author = {Guilbert, HE and Gauthier, DJ}, Title = {Enhancing heralding efficiency and biphoton rate in type-I spontaneous parametric down-conversion}, Journal = {Ieee Journal of Selected Topics in Quantum Electronics}, Volume = {21}, Number = {3}, Pages = {215-224}, Publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, Year = {2015}, Month = {January}, ISSN = {1077-260X}, url = {http://dx.doi.org/10.1109/JSTQE.2014.2375161}, Abstract = {© 2014 IEEE. The nonlinear optical process of spontaneous parametric down-conversion (SPDC) is widely studied for applications in quantum information science due to its ability to produce two photons that can be entangled in many degrees of freedom. For applications in quantum communication, two metrics of this process are particularly important: heralding efficiency and total joint rate. Here, we derive expressions for both quantities for a variety of different beam geometries and frequencies. We pay specific attention to the spectrum of both biphotons and individual photons. We reveal the underlying mechanisms responsible for the spectral shape and show they differ for different geometries and frequencies. We then use these spectra to calculate heralding efficiency and joint count rate and examine how each of these metrics changes with different geometries, frequencies, spectral filtering, and beam parameters. Interestingly, we find very high heralding efficiencies are achievable for collinear geometries without spectral filtering, while noncollinear geometries require spectral filtering to achieve the same values. We also find that the spectrum is narrower for nondegenerate SPDC than for degenerate SPDC, leading to lower joint count rates and higher heralding efficiency in the former. In addition to the theory, we verify selected predictions with experimental results.}, Doi = {10.1109/JSTQE.2014.2375161}, Key = {fds246227} } @article{fds321996, Author = {Baron, A and Hoang, TB and Fang, C and Larouche, S and Gauthier, DJ and Mikkelsen, MH and Smith, DR}, Title = {Nonlinear Metal/Dielectric Plasmonic Interfaces}, Journal = {Nonlinear Optics, Nlo 2015}, Publisher = {OSA}, Year = {2015}, Month = {January}, ISBN = {9781557520012}, url = {http://dx.doi.org/10.1364/NLO.2015.NTu2B.2}, Abstract = {© 2015 OSA. We investigate theoretically and experimentally the optical nonlinearity of metal/dielectric interfaces, which provides a metric that predicts the scaling of self-action as well as a means to measure χ(3)of gold using surface plasmon polaritons.}, Doi = {10.1364/NLO.2015.NTu2B.2}, Key = {fds321996} } @article{fds246220, Author = {Gauthier, DJ and Lohmann, J and Haynes, ND and D'Huys, O and Schöll, E}, Title = {Dynamics of experimental time-delay autonomous Boolean networks}, Year = {2015}, Month = {January}, Key = {fds246220} } @article{fds246221, Author = {Gauthier, DJ and Haynes, ND and Soriano, MC and Rosin, DP and Fischer, I}, Title = {Physical reservoir computing with Boolean logic}, Year = {2015}, Month = {January}, Key = {fds246221} } @article{fds246222, Author = {Gauthier, DJ and Haynes, ND and Lohmann, J and D'Huys, O and Rosin, DP}, Title = {Extreme transients in time-delay autonomous Boolean networks}, Year = {2015}, Month = {January}, Key = {fds246222} } @article{fds246224, Author = {Weicker, L and Erneux, T and Rosin, DP and Gauthier, DJ}, Title = {Multirhythmicity in an optoelectronic oscillator with large delay.}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {91}, Number = {1}, Pages = {012910}, Publisher = {American Physical Society (APS)}, Year = {2015}, Month = {January}, ISSN = {1539-3755}, url = {http://dx.doi.org/10.1103/physreve.91.012910}, Abstract = {An optoelectronic oscillator exhibiting a large delay in its feedback loop is studied both experimentally and theoretically. We show that multiple square-wave oscillations may coexist for the same values of the parameters (multirhythmicity). Depending on the sign of the phase shift, these regimes admit either periods close to an integer fraction of the delay or periods close to an odd integer fraction of twice the delay. These periodic solutions emerge from successive Hopf bifurcation points and stabilize at a finite amplitude following a scenario similar to Eckhaus instability in spatially extended systems. We find quantitative agreements between experiments and numerical simulations. The linear stability of the square waves is substantiated analytically by determining the stable fixed points of a map.}, Doi = {10.1103/physreve.91.012910}, Key = {fds246224} } @article{fds246223, Author = {Gauthier, DJ and Schmittberger, BL}, Title = {Enhancing the nonlinearity at ultra-low light levels using spatial bunching of cold atoms}, Year = {2015}, Month = {February}, Key = {fds246223} } @article{fds246212, Author = {Haynes, ND and Soriano, MC and Rosin, DP and Fischer, I and Gauthier, DJ}, Title = {Reservoir computing with a single time-delay autonomous Boolean node}, Journal = {Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics}, Volume = {91}, Number = {2}, Pages = {020801}, Year = {2015}, Month = {February}, ISSN = {1539-3755}, url = {http://dx.doi.org/10.1103/PhysRevE.91.020801}, Abstract = {© 2015 American Physical Society. We demonstrate reservoir computing with a physical system using a single autonomous Boolean logic element with time-delay feedback. The system generates a chaotic transient with a window of consistency lasting between 30 and 300 ns, which we show is sufficient for reservoir computing. We then characterize the dependence of computational performance on system parameters to find the best operating point of the reservoir. When the best parameters are chosen, the reservoir is able to classify short input patterns with performance that decreases over time. In particular, we show that four distinct input patterns can be classified for 70 ns, even though the inputs are only provided to the reservoir for 7.5 ns.}, Doi = {10.1103/PhysRevE.91.020801}, Key = {fds246212} } @article{fds246210, Author = {Mirhosseini, M and Magaña-Loaiza, OS and O'Sullivan, MN and Rodenburg, B and Malik, M and Lavery, MPJ and Padgett, MJ and Gauthier, DJ and Boyd, RW}, Title = {High-dimensional quantum cryptography with twisted light}, Journal = {New Journal of Physics}, Volume = {17}, Number = {3}, Pages = {1-12}, Publisher = {IOP Publishing}, Year = {2015}, Month = {March}, url = {http://dx.doi.org/10.1088/1367-2630/17/3/033033}, Abstract = {© 2015 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Quantum key distribution (QKD) systems often rely on polarization of light for encoding, thus limiting the amount of information that can be sent per photon and placing tight bounds on the error rates that such a system can tolerate. Here we describe a proof-of-principle experiment that indicates the feasibility of high-dimensional QKD based on the transverse structure of the light field allowing for the transfer of more than 1 bit per photon. Our implementation uses the orbital angular momentum (OAM) of photons and the corresponding mutually unbiased basis of angular position (ANG). Our experiment uses a digital micro-mirror device for the rapid generation of OAM and ANG modes at 4 kHz, and a mode sorter capable of sorting single photons based on their OAM and ANG content with a separation efficiency of 93%. Through the use of a seven-dimensional alphabet encoded in the OAM and ANG bases, we achieve a channel capacity of 2.05 bits per sifted photon. Our experiment demonstrates that, in addition to having an increased information capacity, multilevel QKD systems based on spatial-mode encoding can be more resilient against intercept-resend eavesdropping attacks.}, Doi = {10.1088/1367-2630/17/3/033033}, Key = {fds246210} } @article{fds303662, Author = {Gauthier, DJ and Rosin, DP and Rontani, D and Schöll, E}, Title = {Experimental signatures of chimera states in non-locally coupled Boolean phase oscillators}, Year = {2015}, Month = {March}, Key = {fds303662} } @article{fds303663, Author = {Gauthier, DJ and Haynes, ND and Rosin, DP and Rontani, D}, Title = {Towards reservoir computing with time-delay autonomous Boolean networks}, Year = {2015}, Month = {March}, Key = {fds303663} } @article{fds246207, Author = {Rivera-Durón, RR and Campos-Cantón, E and Campos-Cantón, I and Gauthier, DJ}, Title = {Forced synchronization of autonomous dynamical Boolean networks.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {25}, Number = {8}, Pages = {083113}, Year = {2015}, Month = {August}, ISSN = {1054-1500}, url = {http://dx.doi.org/10.1063/1.4928739}, Abstract = {We present the design of an autonomous time-delay Boolean network realized with readily available electronic components. Through simulations and experiments that account for the detailed nonlinear response of each circuit element, we demonstrate that a network with five Boolean nodes displays complex behavior. Furthermore, we show that the dynamics of two identical networks display near-instantaneous synchronization to a periodic state when forced by a common periodic Boolean signal. A theoretical analysis of the network reveals the conditions under which complex behavior is expected in an individual network and the occurrence of synchronization in the forced networks. This research will enable future experiments on autonomous time-delay networks using readily available electronic components with dynamics on a slow enough time-scale so that inexpensive data collection systems can faithfully record the dynamics.}, Doi = {10.1063/1.4928739}, Key = {fds246207} } @article{fds322482, Author = {Baron, A and Larouche, S and Gauthier, DJ and Smith, DR}, Title = {Scaling of the nonlinear response of metal/dielectric plasmonic waveguides}, Journal = {Conference on Lasers and Electro Optics Europe Technical Digest}, Volume = {2015-August}, Year = {2015}, Month = {August}, ISBN = {9781557529688}, Abstract = {© 2015 OSA. The scaling of the nonlinear response of a single-interface plasmonic waveguide is studied, where both the metal and dielectric display nonlinearity. We introduce a figure-of-merit that guides metal/dielectric nanophotonic device design for specific applications.}, Key = {fds322482} } @article{fds322481, Author = {Guilbert, HE and Gauthier, DJ}, Title = {Erratum: Enhancing heralding efficiency and biphoton rate in Type-I spontaneous parametric down-conversion (IEEE Journal on Selected Topics in Quantum Electronics (2015) 21:15)}, Journal = {Ieee Journal of Selected Topics in Quantum Electronics}, Volume = {21}, Number = {5}, Pages = {1-1}, Publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, Year = {2015}, Month = {September}, url = {http://dx.doi.org/10.1109/JSTQE.2015.2450366}, Doi = {10.1109/JSTQE.2015.2450366}, Key = {fds322481} } @article{fds329843, Author = {Stipcevic, M and Christensen, BG and Kwiat, PG and Gauthier, DJ}, Title = {Advanced active quenching circuits for single-photon avalanche photodiodes}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {9858}, Publisher = {SPIE}, Year = {2016}, Month = {January}, ISBN = {9781510600997}, url = {http://dx.doi.org/10.1117/12.2227999}, Abstract = {© 2016 SPIE. Commercial photon-counting modules, often based on actively quenched solid-state avalanche photodiode sensors, are used in wide variety of applications. Manufacturers characterize their detectors by specifying a small set of parameters, such as detection efficiency, dead time, dark counts rate, afterpulsing probability and single photon arrival time resolution (jitter), however they usually do not specify the conditions under which these parameters are constant or present a sufficient description. In this work, we present an in-depth analysis of the active quenching process and identify intrinsic limitations and engineering challenges. Based on that, we investigate the range of validity of the typical parameters used by two commercial detectors. We identify an additional set of imperfections that must be specified in order to sufficiently characterize the behavior of single-photon counting detectors in realistic applications. The additional imperfections include rate-dependence of the dead time, jitter, detection delay shift, and «twilighting.» Also, the temporal distribution of afterpulsing and various artifacts of the electronics are important. We find that these additional non-ideal behaviors can lead to unexpected effects or strong deterioration of the system's performance. Specifically, we discuss implications of these new findings in a few applications in which single-photon detectors play a major role: the security of a quantum cryptographic protocol, the quality of single-photon-based random number generators and a few other applications. Finally, we describe an example of an optimized avalanche quenching circuit for a high-rate quantum key distribution system based on time-bin entangled photons.}, Doi = {10.1117/12.2227999}, Key = {fds329843} } @article{fds324414, Author = {Islam, NT and Cahall, C and Aragoneses, A and Lim, CCW and Allman, MS and Verma, V and Nam, SW and Kim, J and Gauthier, DJ}, Title = {Enhancing the secure key rate in a quantum-key-distribution system using discrete-variable, high-dimensional, time-frequency states}, Journal = {Smart Structures and Materials 2005: Active Materials: Behavior and Mechanics}, Volume = {9996}, Publisher = {SPIE}, Year = {2016}, Month = {January}, ISBN = {9781510603967}, url = {http://dx.doi.org/10.1117/12.2241429}, Abstract = {© 2016 SPIE. High-dimensional (dimension d > 2) quantum key distribution (QKD) protocols that encode information in the temporal degree of freedom promise to overcome some of the challenges of qubit-based (d = 2) QKD systems. In particular, the long recovery time of single-photon detectors and large channel noise at long distance both limit the rate at which a final secure key can be generated in a low-dimension QKD system. We propose and demonstrate a practical discrete-variable time-frequency protocol with d = 4 at a wavelength of 1550 nm, where the temporal states are secured by transmitting and detecting their dual states under Fourier transformation, known as the frequency-basis states, augmented by a decoy-state protocol. We show that the discrete temporal and frequency states can be generated and detected using commercially-available equipment with high timing and spectral efficiency. In our initial experiments, we only have access to detectors that have low efficiency (1%) at 1550 nm. Together with other component losses, our system is equivalent to a QKD system with ideal components and a 50-km-long optical-fiber quantum channel. We find that our system maintains a spectral visibility of over 99.0% with a quantum bit error rate of 2.3%, which is largely due to the finite extinction ratio of the intensity modulators used in the transmitter. The estimated secure key rate of this system is 7.7×104 KHz, which should improve drastically when we use detectors optimized for 1550 nm.}, Doi = {10.1117/12.2241429}, Key = {fds324414} } @article{fds324413, Author = {Schmittberger, BL and Gauthier, DJ}, Title = {Transverse optical and atomic pattern formation}, Journal = {Journal of the Optical Society of America B}, Volume = {33}, Number = {7}, Pages = {1543-1551}, Publisher = {The Optical Society}, Year = {2016}, Month = {July}, url = {http://dx.doi.org/10.1364/JOSAB.33.001543}, Abstract = {© 2016 Optical Society of America. The study of transverse optical pattern formation has been studied extensively in nonlinear optics, with a recent experimental interest in studying the phenomenon using cold atoms, which can undergo real-space self-organization. Here, we describe our experimental observation of pattern formation in cold atoms, which occurs using less than 1 W of applied power. We show that the optical patterns and the self-organized atomic structures undergo continuous symmetry breaking, which is characteristic of nonequilibrium phenomena in a multimode system. To theoretically describe pattern formation in cold atoms, we present a self-consistent model that allows for tight atomic bunching in the applied optical lattice. We derive the nonlinear refractive index of a gas of multilevel atoms in an optical lattice, and we derive the threshold conditions under which pattern formation occurs. We show that by using small detunings and sub-Doppler temperatures, one achieves intensity thresholds for pattern formation that are reduced by two orders of magnitude compared to warm atoms.}, Doi = {10.1364/JOSAB.33.001543}, Key = {fds324413} } @article{fds324412, Author = {D'Huys, O and Lohmann, J and Haynes, ND and Gauthier, DJ}, Title = {Super-transient scaling in time-delay autonomous Boolean network motifs.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {26}, Number = {9}, Pages = {094810}, Year = {2016}, Month = {September}, url = {http://dx.doi.org/10.1063/1.4954274}, Abstract = {Autonomous Boolean networks are commonly used to model the dynamics of gene regulatory networks and allow for the prediction of stable dynamical attractors. However, most models do not account for time delays along the network links and noise, which are crucial features of real biological systems. Concentrating on two paradigmatic motifs, the toggle switch and the repressilator, we develop an experimental testbed that explicitly includes both inter-node time delays and noise using digital logic elements on field-programmable gate arrays. We observe transients that last millions to billions of characteristic time scales and scale exponentially with the amount of time delays between nodes, a phenomenon known as super-transient scaling. We develop a hybrid model that includes time delays along network links and allows for stochastic variation in the delays. Using this model, we explain the observed super-transient scaling of both motifs and recreate the experimentally measured transient distributions.}, Doi = {10.1063/1.4954274}, Key = {fds324412} } @article{fds329842, Author = {Brougham, T and Wildfeuer, CF and Barnett, SM and Gauthier, DJ}, Title = {The information of high-dimensional time-bin encoded photons}, Journal = {The European Physical Journal D}, Volume = {70}, Number = {10}, Publisher = {Springer Nature}, Year = {2016}, Month = {October}, url = {http://dx.doi.org/10.1140/epjd/e2016-70357-4}, Abstract = {© 2016, The Author(s). Abstract: High-dimensional entanglement is an important physical resource for quantumcommunication. A basic issue for any communication scheme is how many shared bits twoparties can extract subject to experimental noise. We determine the shared informationthat can be extracted from time-bin entangled photons using frame encoding. We considerphotons generated by a general down-conversion source and also model losses, dark countsand the effects of multiple photons within each frame. Furthermore, we describe aprocedure for including other imperfections such as after-pulsing, detector dead-times andjitter. The results are illustrated by deriving analytic expressions for the maximuminformation that can be extracted from high-dimensional time-binentangled photons generated by down conversion. A key finding is that under realisticconditions and using standard SPAD detectors one can still choose the frame size so as toextract over 10 bits per photon. These results are thus useful forexperiments on high-dimensional quantum-key distribution systems, but are not limited tosuch systems. For example, the results are also useful for determining the limits of fibrearrays or within time-multiplexing schemes. Graphical abstract: [Figure not available: see fulltext.]}, Doi = {10.1140/epjd/e2016-70357-4}, Key = {fds329842} } @article{fds324411, Author = {Schmittberger, BL and Gauthier, DJ}, Title = {Spontaneous emergence of free-space optical and atomic patterns}, Journal = {New Journal of Physics}, Volume = {18}, Number = {10}, Pages = {103021-103021}, Publisher = {IOP Publishing}, Year = {2016}, Month = {October}, url = {http://dx.doi.org/10.1088/1367-2630/18/10/103021}, Abstract = {� 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. The spontaneous formation of patterns in dynamical systems is a rich phenomenon that transcends scientific boundaries. Here, we report our observation of coupled optical-atomic pattern formation, which results in the creation of self-organized, multimode structures in free-space laser-driven cold atoms. We show that this process gives rise to spontaneous three-dimensional Sisyphus cooling even at very low light intensities and the emergence of self-organized structures on both sub- and super-wavelength scales.}, Doi = {10.1088/1367-2630/18/10/103021}, Key = {fds324411} } @article{fds324409, Author = {Islam, NT and Cahall, C and Aragoneses, A and Lim, CCW and Allman, MS and Verma, V and Nam, SW and Kim, J and Gauthier, DJ}, Title = {Discrete-variable time-frequency quantum key distribution}, Journal = {2016 Conference on Lasers and Electro Optics, Cleo 2016}, Year = {2016}, Month = {December}, ISBN = {9781943580118}, Abstract = {© 2016 OSA. We demonstrate a setup for realizing a four-dimensional time-frequency quantum key distribution protocol, where discrete temporal states are secured using discrete frequency states. The high-dimensional frequency states are detected using a tree of passively stabilized time-delay interferometers.}, Key = {fds324409} } @article{fds324410, Author = {Cahall, CT and Gauthier, DJ and Kim, J}, Title = {Cryogenic amplifiers for a superconducting nanowire single photon detector system}, Journal = {2016 Conference on Lasers and Electro Optics, Cleo 2016}, Year = {2016}, Month = {December}, ISBN = {9781943580118}, Abstract = {© 2016 OSA. We study an electrical readout scheme for superconducting nanowire single photon detectors using commercial off-the-shelf amplifiers operating at cryogenic temperatures. Low power consumption and improved noise performance enable multichannel readout circuit solution with high timing resolution.}, Key = {fds324410} } @article{fds325800, Author = {Lohmann, J and D'Huys, O and Haynes, ND and Schöll, E and Gauthier, DJ}, Title = {Transient dynamics and their control in time-delay autonomous Boolean ring networks.}, Journal = {Physical Review. E}, Volume = {95}, Number = {2-1}, Pages = {022211}, Year = {2017}, Month = {February}, url = {http://dx.doi.org/10.1103/physreve.95.022211}, Abstract = {Biochemical systems with switch-like interactions, such as gene regulatory networks, are well modeled by autonomous Boolean networks. Specifically, the topology and logic of gene interactions can be described by systems of continuous piecewise-linear differential equations, enabling analytical predictions of the dynamics of specific networks. However, most models do not account for time delays along links associated with spatial transport, mRNA transcription, and translation. To address this issue, we have developed an experimental test bed to realize a time-delay autonomous Boolean network with three inhibitory nodes, known as a repressilator, and use it to study the dynamics that arise as time delays along the links vary. We observe various nearly periodic oscillatory transient patterns with extremely long lifetime, which emerge in small network motifs due to the delay, and which are distinct from the eventual asymptotically stable periodic attractors. For repeated experiments with a given network, we find that stochastic processes give rise to a broad distribution of transient times with an exponential tail. In some cases, the transients are so long that it is doubtful the attractors will ever be approached in a biological system that has a finite lifetime. To counteract the long transients, we show experimentally that small, occasional perturbations applied to the time delays can force the trajectories to rapidly approach the attractors.}, Doi = {10.1103/physreve.95.022211}, Key = {fds325800} } @article{fds331386, Author = {Islam, NT and Cahall, C and Aragoneses, A and Lezama, A and Kim, J and Gauthier, DJ}, Title = {Robust and Stable Delay Interferometers with Application to d -Dimensional Time-Frequency Quantum Key Distribution}, Journal = {Physical Review Applied}, Volume = {7}, Number = {4}, Publisher = {American Physical Society (APS)}, Year = {2017}, Month = {April}, url = {http://dx.doi.org/10.1103/PhysRevApplied.7.044010}, Abstract = {© 2017 American Physical Society. We experimentally investigate a cascade of temperature-compensated unequal-path interferometers that can be used to measure frequency states in a high-dimensional quantum distribution system. In particular, we demonstrate that commercially available interferometers have sufficient environmental isolation so that they maintain an interference visibility greater than 98.5% at a wavelength of 1550 nm over extended periods with only moderate passive control of the interferometer temperature (<±0.50 °C). Specifically, we characterize two interferometers that have matched delays: one with a free spectral range of 2.5 GHz and the other with 1.25 GHz. We find that the relative path of these interferometers drifts less than 3 nm over a period of 1 h during which the temperature fluctuates by <±0.10 °C. When we purposely heat the interferometers over a temperature range of 20-50 °C, we measure a path-length shift of 26±9 nm/°C for the 2.5-GHz interferometer. For the 1.25-GHz interferometer, the path-length shift is nonlinear and is locally equal to zero at a temperature of 37.1 °C and is 50±17 nm/°C at 22 °C. With these devices, we realize a proof-of-concept quantum key distribution experiment and achieve quantum bit error rates of 1.94% and 3.69% in time and frequency basis, respectively, at a quantum channel loss of 14 dB.}, Doi = {10.1103/PhysRevApplied.7.044010}, Key = {fds331386} } @article{fds329841, Author = {Shea, ME and Gauthier, DJ}, Title = {Comment on "Nondestructive light-shift measurements of single atoms in optical dipole traps"}, Journal = {Physical Review A}, Volume = {96}, Number = {2}, Publisher = {American Physical Society (APS)}, Year = {2017}, Month = {August}, url = {http://dx.doi.org/10.1103/PhysRevA.96.027401}, Abstract = {© 2017 American Physical Society. The light shift caused by an optical dipole force trap on a single Rb87 atom was recently studied by Shih and Chapman [Phys. Rev. A 87, 063408 (2013)PLRAAN1050-294710.1103/PhysRevA.87.063408] using a dipole-matrix-element-based approach. A separate study by Neuzner et al. [Phys. Rev. A 92, 053842 (2015)PLRAAN1050-294710.1103/PhysRevA.92.053842] considered the same system using a polarizability-based approach. We find that the results of these two studies do not agree, which we ascribe to an error in the theoretical part of Shih and Chapman's paper. We correct this error, offer an alternative formulation for the energy-level shift using the matrix-element-based approach, and find good agreement between our predictions and those obtained with the polarizability-based method. Furthermore, our predictions are in better agreement with Shih and Chapman's experimental results in comparison to their predictions. In contrast to the polarizability-based method, our formulation can be easily extended to different trapping wavelengths and atomic species.}, Doi = {10.1103/PhysRevA.96.027401}, Key = {fds329841} } @article{fds329840, Author = {Stipčević, M and Christensen, BG and Kwiat, PG and Gauthier, DJ}, Title = {Advanced active quenching circuit for ultrafast quantum cryptography}, Journal = {Optics Express}, Volume = {25}, Number = {18}, Pages = {21861-21876}, Publisher = {The Optical Society}, Year = {2017}, Month = {September}, url = {http://dx.doi.org/10.1364/OE.25.021861}, Abstract = {© 2017 Optical Society of America. Commercial photon-counting modules based on actively quenched solid-state avalanche photodiode sensors are used in a wide variety of applications. Manufacturers characterize their detectors by specifying a small set of parameters, such as detection efficiency, dead time, dark counts rate, afterpulsing probability and single-photon arrival-time resolution (jitter). However, they usually do not specify the range of conditions over which these parameters are constant or present a sufficient description of the characterization process. In this work, we perform a few novel tests on two commercial detectors and identify an additional set of imperfections that must be specified to sufficiently characterize their behavior. These include rate-dependence of the dead time and jitter, detection delay shift, and "twilighting". We find that these additional non-ideal behaviors can lead to unexpected effects or strong deterioration of the performance of a system using these devices. We explain their origin by an in-depth analysis of the active quenching process. To mitigate the effects of these imperfections, a custom-built detection system is designed using a novel active quenching circuit. Its performance is compared against two commercial detectors in a fast quantum key distribution system with hyper-entangled photons and a random number generator.}, Doi = {10.1364/OE.25.021861}, Key = {fds329840} } @article{fds331604, Author = {Islam, NT and Lim, CCW and Cahall, C and Kim, J and Gauthier, DJ}, Title = {Provably secure and high-rate quantum key distribution with time-bin qudits.}, Journal = {Science Advances}, Volume = {3}, Number = {11}, Pages = {e1701491}, Year = {2017}, Month = {November}, url = {http://dx.doi.org/10.1126/sciadv.1701491}, Abstract = {The security of conventional cryptography systems is threatened in the forthcoming era of quantum computers. Quantum key distribution (QKD) features fundamentally proven security and offers a promising option for quantum-proof cryptography solution. Although prototype QKD systems over optical fiber have been demonstrated over the years, the key generation rates remain several orders of magnitude lower than current classical communication systems. In an effort toward a commercially viable QKD system with improved key generation rates, we developed a discrete-variable QKD system based on time-bin quantum photonic states that can generate provably secure cryptographic keys at megabit-per-second rates over metropolitan distances. We use high-dimensional quantum states that transmit more than one secret bit per received photon, alleviating detector saturation effects in the superconducting nanowire single-photon detectors used in our system that feature very high detection efficiency (of more than 70%) and low timing jitter (of less than 40 ps). Our system is constructed using commercial off-the-shelf components, and the adopted protocol can be readily extended to free-space quantum channels. The security analysis adopted to distill the keys ensures that the demonstrated protocol is robust against coherent attacks, finite-size effects, and a broad class of experimental imperfections identified in our system.}, Doi = {10.1126/sciadv.1701491}, Key = {fds331604} } @article{fds331603, Author = {Cahall, C and Nicolich, KL and Islam, NT and Lafyatis, GP and Miller, AJ and Gauthier, DJ and Kim, J}, Title = {Multi-photon detection using a conventional superconducting nanowire single-photon detector}, Journal = {Optica}, Volume = {4}, Number = {12}, Pages = {1534-1535}, Publisher = {The Optical Society}, Year = {2017}, Month = {December}, url = {http://dx.doi.org/10.1364/OPTICA.4.001534}, Abstract = {© 2017 Optical Society of America. We present the first evidence of multi-photon detection using a conventional superconducting nanowire single-photon detector, indicating number resolution up to four photons. The observed multi-photon detection statistics are consistent with the predictions of our model.}, Doi = {10.1364/OPTICA.4.001534}, Key = {fds331603} } @article{fds335581, Author = {Islam, NT and Lim, CCW and Cahall, C and Qi, B and Kim, J and Gauthier, DJ}, Title = {High-rate time-bin quantum key distribution using quantum-controlled measurement}, Journal = {Optics Infobase Conference Papers}, Volume = {Part F93-CLEO_QELS 2018}, Year = {2018}, Month = {January}, ISBN = {9781557528209}, url = {http://dx.doi.org/10.1364/CLEO_QELS.2018.FTu3G.3}, Abstract = {© OSA 2018. We realize a time-bin qudit-based quantum key distribution system that uses two-photon interference for measuring the phase-basis states, allowing us to generate a secret key at a megabits-per-second rate.}, Doi = {10.1364/CLEO_QELS.2018.FTu3G.3}, Key = {fds335581} } @article{fds335582, Author = {Cahall, C and Nicolich, KL and Islam, NT and Lafyatis, GP and Miller, AJ and Gauthier, DJ and Kim, J}, Title = {Photon-number resolution in conventional superconducting nanowire single-photon detectors: Experimental demonstration}, Journal = {Optics Infobase Conference Papers}, Volume = {Part F93-CLEO_QELS 2018}, Publisher = {OSA}, Year = {2018}, Month = {January}, ISBN = {9781557528209}, url = {http://dx.doi.org/10.1364/CLEO_QELS.2018.FW3F.2}, Abstract = {© OSA 2018. We present the first experimental evidence of photon number resolution in a conventional superconducting nanowire single-photon detector. The photon-number-dependent resistance reflected in the rise-time of output pulses is detected using a wideband, low-noise read-out circuit.}, Doi = {10.1364/CLEO_QELS.2018.FW3F.2}, Key = {fds335582} } @article{fds335583, Author = {Nicolich, KL and Cahall, C and Islam, NT and Lafyatis, GP and Kim, J and Gauthier, DJ}, Title = {Photon-number resolution in conventional superconducting nanowire single-photon detectors: Theoretical predictions}, Journal = {Optics Infobase Conference Papers}, Volume = {Part F92-CLEO_AT 2018}, Publisher = {OSA}, Year = {2018}, Month = {January}, ISBN = {9781557528209}, url = {http://dx.doi.org/10.1364/CLEO_AT.2018.JTh2A.8}, Abstract = {© OSA 2018. We demonstrate theoretically that a conventional single-pixel superconducting nanowire single-photon detector can resolve photon number by sensing changes in the rising edge of the electrical readout pulse.}, Doi = {10.1364/CLEO_AT.2018.JTh2A.8}, Key = {fds335583} } @article{fds340759, Author = {Lukens, JM and Islam, NT and Lim, CCW and Gauthier, DJ}, Title = {Mutually unbiased bases for time-bin qudits}, Journal = {Optics Infobase Conference Papers}, Volume = {Part F114-FIO 2018}, Publisher = {OSA}, Year = {2018}, Month = {January}, ISBN = {9781943580460}, url = {http://dx.doi.org/10.1364/FIO.2018.JW3A.66}, Abstract = {© 2018 The Author(s). We introduce a method for generation and detection of mutually unbiased bases for time-bin qudits employing electro-optic phase modulator - coded fiber Bragg grating pairs. Our approach uses one spatial mode and can switch rapidly between bases.}, Doi = {10.1364/FIO.2018.JW3A.66}, Key = {fds340759} } @article{fds333671, Author = {Lukens, JM and Islam, NT and Lim, CCW and Gauthier, DJ}, Title = {Reconfigurable generation and measurement of mutually unbiased bases for time-bin qudits}, Journal = {Applied Physics Letters}, Volume = {112}, Number = {11}, Pages = {111102-111102}, Publisher = {AIP Publishing}, Year = {2018}, Month = {March}, url = {http://dx.doi.org/10.1063/1.5024318}, Abstract = {© 2018 Author(s). We propose a method for implementing mutually unbiased generation and measurement of time-bin qudits using a cascade of electro-optic phase modulator-coded fiber Bragg grating pairs. Our approach requires only a single spatial mode and can switch rapidly between basis choices. We obtain explicit solutions for dimensions d = 2, 3, and 4 that realize all d + 1 possible mutually unbiased bases and analyze the performance of our approach in quantum key distribution. Given its practicality and compatibility with current technology, our approach provides a promising springboard for scalable processing of high-dimensional time-bin states.}, Doi = {10.1063/1.5024318}, Key = {fds333671} } @article{fds335580, Author = {Islam, NT and Lim, CCW and Cahall, C and Kim, J and Gauthier, DJ}, Title = {Securing quantum key distribution systems using fewer states}, Journal = {Physical Review A}, Volume = {97}, Number = {4}, Publisher = {American Physical Society (APS)}, Year = {2018}, Month = {April}, url = {http://dx.doi.org/10.1103/PhysRevA.97.042347}, Abstract = {© 2018 American Physical Society. Quantum key distribution (QKD) allows two remote users to establish a secret key in the presence of an eavesdropper. The users share quantum states prepared in two mutually unbiased bases: one to generate the key while the other monitors the presence of the eavesdropper. Here, we show that a general d-dimension QKD system can be secured by transmitting only a subset of the monitoring states. In particular, we find that there is no loss in the secure key rate when dropping one of the monitoring states. Furthermore, it is possible to use only a single monitoring state if the quantum bit error rates are low enough. We apply our formalism to an experimental d=4 time-phase QKD system, where only one monitoring state is transmitted, and obtain a secret key rate of 17.4±2.8 Mbits/s at a 4 dB channel loss and with a quantum bit error rate of 0.045±0.001 and 0.037±0.001 in time and phase bases, respectively, which is 58.4% of the secret key rate that can be achieved with the full setup. This ratio can be increased, potentially up to 100%, if the error rates in time and phase basis are reduced. Our results demonstrate that it is possible to substantially simplify the design of high-dimensional QKD systems, including those that use the spatial or temporal degrees of freedom of the photon, and still outperform qubit-based (d=2) protocols.}, Doi = {10.1103/PhysRevA.97.042347}, Key = {fds335580} } @article{fds335579, Author = {Cahall, C and Gauthier, DJ and Kim, J}, Title = {Scalable cryogenic readout circuit for a superconducting nanowire single-photon detector system.}, Journal = {Review of Scientific Instruments}, Volume = {89}, Number = {6}, Pages = {063117}, Year = {2018}, Month = {June}, url = {http://dx.doi.org/10.1063/1.5018179}, Abstract = {The superconducting nanowire single-photon detector (SNSPD) is a leading technology for quantum information science applications using photons, and is finding increasing uses in photon-starved classical imaging applications. Critical detector characteristics, such as timing resolution (jitter), reset time, and maximum count rate, are heavily influenced by the readout electronics that sense and amplify the photon detection signal. We describe a readout circuit for SNSPDs using commercial off-the-shelf amplifiers operating at cryogenic temperatures. Our design demonstrates a 35 ps timing resolution and a maximum count rate of over 2 × 107 counts per second, while maintaining <3 mW power consumption per channel, making it suitable for a multichannel readout.}, Doi = {10.1063/1.5018179}, Key = {fds335579} } @article{fds337437, Author = {Aragoneses, A and Islam, NT and Eggleston, M and Lezama, A and Kim, J and Gauthier, DJ}, Title = {Bounding the outcome of a two-photon interference measurement using weak coherent states.}, Journal = {Optics Letters}, Volume = {43}, Number = {16}, Pages = {3806-3809}, Publisher = {OPTICAL SOC AMER}, Year = {2018}, Month = {August}, url = {http://dx.doi.org/10.1364/ol.43.003806}, Abstract = {The interference of two photons at a beam splitter is at the core of many quantum photonic technologies, such as quantum key distribution or linear-optics quantum computing. Observing high-visibility interference is challenging because of the difficulty of realizing indistinguishable single-photon sources. Here, we perform a two-photon interference experiment using phase-randomized weak coherent states with different mean photon numbers. We place a tight upper bound on the expected coincidences for the case when the incident wavepackets contain single photons, allowing us to observe the Hong-Ou-Mandel effect. We find that the interference visibility is at least as large as 0.995-0.013+0.005.}, Doi = {10.1364/ol.43.003806}, Key = {fds337437} } @article{fds337725, Author = {Islam, NT and Lim, CCW and Cahall, C and Qi, B and Kim, J and Gauthier, DJ}, Title = {High-rate Time-bin Quantum Key Distribution Using Quantum-controlled Measurement}, Journal = {2018 Conference on Lasers and Electro Optics, Cleo 2018 Proceedings}, Year = {2018}, Month = {August}, ISBN = {9781943580422}, Abstract = {© 2018 OSA. We realize a time-bin qudit-based quantum key distribution system that uses two-photon interference for measuring the phase-basis states, allowing us to generate a secret key at a megabits-per-second rate.}, Key = {fds337725} } @article{fds337724, Author = {Nicolich, KL and Cahall, C and Islam, NT and Lafyatis, GP and Kim, J and Gauthier, DJ}, Title = {Photon-Number Resolution in Conventional Superconducting Nanowire Single-Photon Detectors: Theoretical Predictions}, Journal = {2018 Conference on Lasers and Electro Optics, Cleo 2018 Proceedings}, Year = {2018}, Month = {August}, ISBN = {9781943580422}, Abstract = {© 2018 OSA. We demonstrate theoretically that a conventional single-pixel superconducting nanowire single-photon detector can resolve photon number by sensing changes in the rising edge of the electrical readout pulse.}, Key = {fds337724} } @article{fds337611, Author = {Cahall, C and Nicolich, KL and Islam, NT and Lafyatis, GP and Miller, AJ and Gauthier, DJ and Kim, J}, Title = {Photon-Number Resolution in Conventional Superconducting Nanowire Single-photon Detectors: Experimental Demonstration}, Journal = {2018 Conference on Lasers and Electro Optics, Cleo 2018 Proceedings}, Year = {2018}, Month = {August}, ISBN = {9781943580422}, Abstract = {© 2018 OSA. We present the first experimental evidence of photon number resolution in a conventional superconducting nanowire single-photon detector. The photon-number-dependent resistance reflected in the rise-time of output pulses is detected using a wideband, low-noise read-out circuit.}, Key = {fds337611} } @article{fds341506, Author = {Canaday, D and Griffith, A and Gauthier, DJ}, Title = {Rapid time series prediction with a hardware-based reservoir computer.}, Journal = {Chaos (Woodbury, N.Y.)}, Volume = {28}, Number = {12}, Pages = {123119}, Year = {2018}, Month = {December}, url = {http://dx.doi.org/10.1063/1.5048199}, Abstract = {Reservoir computing is a neural network approach for processing time-dependent signals that has seen rapid development in recent years. Physical implementations of the technique using optical reservoirs have demonstrated remarkable accuracy and processing speed at benchmark tasks. However, these approaches require an electronic output layer to maintain high performance, which limits their use in tasks such as time-series prediction, where the output is fed back into the reservoir. We present here a reservoir computing scheme that has rapid processing speed both by the reservoir and the output layer. The reservoir is realized by an autonomous, time-delay, Boolean network configured on a field-programmable gate array. We investigate the dynamical properties of the network and observe the fading memory property that is critical for successful reservoir computing. We demonstrate the utility of the technique by training a reservoir to learn the short- and long-term behavior of a chaotic system. We find accuracy comparable to state-of-the-art software approaches of a similar network size, but with a superior real-time prediction rate up to 160 MHz.}, Doi = {10.1063/1.5048199}, Key = {fds341506} } %% Papers Submitted @article{fds220527, Author = {M. Stipcevic and D.J. Gauthier}, Title = {Precise Monte Carlo simulation of single-photon detectors with active quenching}, Year = {2013}, Month = {September}, Key = {fds220527} } @article{fds220526, Author = {D.P. Rosin and D. Rontani and D.J. Gauthier}, Title = {Synchronization of coupled Boolean phase oscillators,' submitted for publication}, Year = {2013}, Month = {November}, url = {http://arxiv.org/abs/1311.2996}, Key = {fds220526} }