Optical phase conjugation in azo-dye-doped polymer films using pulsed and CW lasers

Abstract

Generation of phase conjugate waves in azo-dye-doped polymer films using high-power pulsed and low-power CW lasers in both four- and two-wave mixing geometries is reported here. The underlying nonlinear mechaisms in each case are identified by studying the influence of various material, geometric and laser parameters on the generation of phase conjugate wave. Experiments have been carried out using pulsed Nd:YAG and CW argon lasers to study the effect of several parameters of phase conjugate reflectivity. The most dominant mechanisms are found to be thermal nonlinearty and saturation of absorption depending on the type of laser-material interaction. The utility of high efficiency and fast response to optical fields shown by the dye-polymer films is also discussed.