Diffraction of light from phase gratings at large modulation depths: transient-grating experiments in liquids at high laser powers

Generation of transient gratings in weakly absorbing liquids with a high-po wer laser gives rise to changes in the fluid's index of refraction that are sufficiently large to produce both multiple diffraction of a probe laser b eam and a time response anomaly. The coupled-wave approach to the solution of the volume diffraction problem is shown to predict the existence of high -order diffraction of the probe beam and the time dependence of the diffrac tion intensity of each order. In addition, criteria for the Raman-Nath and Bragg diffraction regimes are derived from the first-order, coupled-wave eq uations. (C) 1999 Optical Society of America OCIS codes: 050.1950, 050.1960 , 050.2770.