Numerical solution of phase conjugation by diffraction gratings in photorefractive crystals

Abstract

Phase conjugation are optical devices that can generate a time-reversed replica of an incident electromagnetic wave. These devices play an important role in many optical system that require the transmission of optical waves through scattering media such as the atmosphere. Here we present four wave mixing configuration as one of the most important methods of generation and explanation of process of generation phase conjugation light the coupled equation was solved by three methods: undepleted pump approximation exact solution and two wave mixing approximation. Although exact solutions can be derived for four-wave mixing, the results are difficult to use because of the complicated transcendental equation involved. Solved the coupled equations and introduce an approximation in which two-wave mixing is the dominant process. In this approximation, we assume that the grating is dominated by a pair of waves. A comparative study of the diffraction efficiency as a function of fringe spacing, of some commonly used ferroelectric, non-ferroelectric crystals is presented.