摘要：In this paper, a model of two-wave mixing in the
photorefractive crystal, which takes account of the difference in spatial
frequency in a beam, has been built to study the image enhancement effect in
coherent optical amplification. Based on the theoretical analysis of the model,
the gain distribution for each pixel in the signal beam has been obtained. It
shows that the unevenness of the gain is induced by the
difference in spatial frequency in the beam. The factors that impact on the
uniformity of image enhancement have been analyzed. As an example, the effects
of these factors in a given photorefractive crystal have been studied through
simulation.
关键词：Coherent Optical Amplification; Photorefractive Effect; Image Enhancement; Unevenness of Gain
