Selective Erasure for Multiplexed Holograms in Photorefractive Crystal Using Phase Conjugator

摘要

A novel selective erasure method for multiplexed holograms in a photorefractive crystal using a phase conjugator is presented. In this method, the π-phase shift effect on the diffracted beam due to the photorefractive effect is used. There is a π-phase shift between the interference pattern formed by the reading and diffraction beams, and that formed in the recording process. By returning the reading and reconstructed beams to a recording medium with a phase conjugator, the hologram can be selectively erased in parallel with the readout. Therefore, a dynamic selective erasure can be realized without requiring the accurate alignment of the selective erasure beams. The calculations using coupled-wave equations and experiment results demonstrate the implementability of our method. Furthermore, we analytically determine the requisite conditions of incident beams in the selective erasure process for the reduction of the decay of other multiplexed holograms.