Temporal behavior and instabilities of the self-pumped phase conjugation in photorefractive crystals

Abstract

The temporal behavior of the self-pumped phase conjugation in a photorefractive crystal with a variety of forms of the seed is carefully studied using a two-dimensional model which we proposed. For seeds of the small retroreflection and reflection, the model predicts that the self-pumped phase conjugator shows stable output, and the steady-state phase conjugate reflectivity versus the incident angle are in agreement with the experimental results. For the seed of the diffuse scattering, the conjugator shows either stable or unstable output, which is dependent on the incident angle. The frequency of the self-pulsation of the reflectivity increases linearly (or sublinearly) with an increase of the total light intensity. The model also predicts that there is no frequency shift between the input beam and the output phase conjugate beam for stable output. For unstable output there exists a frequency shift of \ifmmode\pm\else\textpm\fi{} a few Hz.