On the Buildup and Decay of Photorefractive Wave Mixing Processes

Photorefractive media have been used for many novel applications in image processing. One interesting use is the novelty filter which is an all optical processor based on the response of two wave mixing (2-WM) or four wave mixing (4-WM) [1,2]. It is obvious that the temporal dymnamics of the wave mixing process is essential to understand such processes. However, since the overall photorefractive dynamics, including the wave mixing part, is described by complicated nonlinear partial differential equations, it is hard to obtain a general solution. The study has been largely limited to steady state behavior and the response of the photorefractive material only, without taking into account the dynamics of the wave coupling effects.