We have obtained the complete polarization dependence of the two-photon absorption coefficient β by measuring the orientational dependence and the contrast ratio of the photocurrent in an Al0.2 Ga0.8 As waveguide autocorrelator at an optical frequency far above the half-bandgap. The measured polarization dependence is consistent with theory and previous picosecond nonlinear transmission experiments. The cubic symmetry of the nonlinearity provides a contrast ratio that exceeds 2, which is larger than would be obtained assuming an isotropic medium and Kleinmann symmetry. This device was used to obtain an autocorrelation of a mode-locked Nd:YLF laser.
© 1997 Optical Society of America
Original Manuscript: December 17, 1996
Revised Manuscript: June 6, 1997
Published: October 20, 1997
M. Mehdi Karkhanehchi, John H. Marsh, and David C. Hutchings, "Polarization dependence of two-photon absorption in an AlGaAs waveguide autocorrelator," Appl. Opt. 36, 7799-7801 (1997)