Abstract

The temporal evolution of optical nonlinearities is an important element in the choice of materials suitable for applications such as optical switches, real-time optical correlators, and optical memories. In this paper, we report a study of the nonlinear optical properties of a (1) saturable absorber (rhodamine 6G) in solution (water and methanol) and also embedded in a polyvinyl alcohol matrix and (2) a thin film of glass doped with CdS_xSe_1-x microcrystallites. The temporal response of the phase-conjugate signal obtained by degenerate four-wave mixing, as well as the dynamic of higher-order resonant signals have been investigated by means of a frequency-doubled picosecond Nd:YAG laser. Intensity-dependent relaxation times have been found for some materials. Merit figures (defined as the ratio between the nonlinear susceptibility and its relaxation time) of these media have been considered for different polarization configurations. Physical mechanisms involved in the grating relaxation for these different media will be discussed.

© 1990 Optical Society of America