瞬态光学研究室知识库

Some dynamic diffraction characteristics of photorefractive holograms are observed in the experiment of holographic recording and fixing in LiNbO3:Ce:Cu crystal. The self-enhancement and self-depletion phenomena as well as the oscillatory characteristic of diffraction during the recording step are reported. By use of our recently presented time-space dynamic theory of two-center holographic recording, the experimental results are theoretically analyzed and numerically simulated. We found that: (1) The self-enhancement in both steps of recording and fixing can obviously enhance the recorded and fixed hologram and thus the nonvolatile diffraction efficiency. (2) There exists an optimal switching time from the recording step to the fixing step for a high diffraction of fixed hologram. (3) During holographic recording there is a spatially changed direction of energy transferring between the two writing beams, and the energy transferring direction will be reversed as the relative phase difference between the induced space-charge field (SCF) and the exciting interference pattern becomes opposite in the sign. (C) 2004 Elsevier B.V. All rights reserved.