光折变晶体多重全息存储衍射效率均匀性的研究

STUDY ON UNIFORMITY OF DIFFRACTION EFFICIENCY OF MULTIPLEX-EXPOSURE HOLOGRAMS IN PHOTOREFRACTIVE CRYSTAL

推导出了全息多重存储时间递减曝光法各幅图象写入时间的解析表达式，研究了时间递减法和循环曝光法单次曝光时间、总曝光时间以及循环次数随存储图象的幅数之间的变化关系，结果表明时间递减法不但对记录系统的要求较低，而且也可获得相当均匀的衍射效率．

The reduced-recording technique for multiplex-exposure holograms in photorefractive crystal was theoretically studied and the close-form solution of the exposure time ti on the order of exposure i was derived. The exposure time on the first order of exposure and the total exposure time of the reduced-recording technique as well as the incremental exposure time,the total exposure time and the number of recording cycles of the incremental recording technique as function of multiplex-storaged holograms,N were investigated- The results suggest that the exposure time on the first order of exposure,the longest exposure time of the reduced-recording technique,is much smaller compared with the recording time constant for large N and it can obtain an uniform diffraction efficiency with the reduced-recording technique.