Publications [#234602] of Warren S. Warren

Journal Articles

1. Tian, P; Warren, WS, Ultrafast measurement of two-photon absorption by loss modulation, Optics Letters, vol. 27 no. 18 (September, 2002), pp. 1634-1636, The Optical Society, ISSN 0146-9592 [doi]
   (last updated on 2026/01/14)

   Abstract:
   We demonstrate a direct and sensitive technique for measuring two-photon absorption (TPA). An intensity-modulated femtosecond laser beam passes through a sample exhibiting TPA. A TPA signal at twice the modulation frequency is then generated and subsequently measured by a lock-in amplifier. The absolute TPA cross section of Rhodamine 6G at 800 nm is found to be (15.3 ± 2.0) × 10^-50 cm⁴ s/photon and agrees well with previously published results obtained with much higher intensity [J. Chem. Phys. 112, 9201 (2000)]. Our method may be especially useful in measuring nonlinear absorptions of nonfluorescent materials. © 2002 Optical Society of America.