光折变晶体中相反通光方向光程差异的观测

报导利用Sagnac干涉仪检测光折变晶体对两束光波所引起的附加相位差．实验表明：光沿两个相反方向通过光折变晶体时存在着附加相位差；这一附加位相差对晶体光轴方位有明显的依赖关系。这就意味着光沿相反方向通过光折变晶体时折射率存在差异。可将这一现象称为光折变晶体的二向相差效应，其起因应当与光折变晶体光扇效应相同。

Testing Optical Path Difference of Two Beams along Opposite Directions in Photorefractive Crystal

It is reported to test the additional phase difference of two beams along two opposite directions in the photorefractive crystal using Sagnac interferometer. The additional phase difference is demonstrated by experiments when two beams of laser transit along two opposite directions in the photorefractive crystal. The experimental results show that the additional phase difference is dependent on the direction of optical axis of the photorefractive crystal. They mean the existence of the additional optical path difference when two beams of laser transit along two opposite directions in the photorefractive crystal. The effect may be named the effect of bilateral phase in the photorefractive crystal. Its cause may be the same as the fanning effect.