热释电效应对光折变全息光栅读出的影响

PYROELECTRIC AFFECTION ON THE READOUT OF PHOTO REFRACTIVE HOLOGRAPHIC GRATING

先用两束０２７ｍＷ的６３２８ｎｍＨｅＮｅ激光在掺Ｍｎ的ＫＮＳＢＮ晶体中记录光折变全息光栅，再用波长为６２１８ｎｍ的准连续染料激光读出，观察到衍射光信号有一个从初始最大值衰减到稳定最小值的暂态过程．初始值对稳定值的比可达７５以上．

The photorefractive holographic grating in a Mn doped K 1- y Na y Ba 2 -x Sr x Nb 5O 15 (KNSBN) is written with two 0 27mW He Ne laser beams (632 6nm) and is read with one quasicontinuous dye laser beam (621 8nm, 1 6mW or less). It is found that the Bragg diffracton suddenly reaches its maximum at the beginning and then decays to its minimum with a time constant of about 0 6s. The ratio of the maximum to the minimum can be higher than 7 5. A theory including pyroelectric effect has been developed and it fits the experiment well.