采用非同时读出条件下的两波耦合实验装置, 以单束光入射Ce:KNSBN光折变晶体, 系统研究了Ce:KNSBN晶体中光扇效应随入射光偏振态、入射光强度、光入射角的变化情况。结果表明异常偏振光入射晶体时光扇效应明显, 且存在明显的入射光强度阈值特性, 入射光强度阈值为38.2 mW/cm2;相同光入射角下, 稳态光扇强度随入射光强度的增强而明显变大;对应相同的入射光强度, 稳态光扇强度随光入射角θ的增大而增大, 当θ为15°时到达峰值, 而后随θ的增大而逐渐减小。同时对光扇效应的入射光强度阈值特性以及稳态光扇强度随入射光偏振态、入射光强度、光入射角的变化作出了相应的物理解释。

A two-wave coupling experimental system is used to study the beam fanning effect in a Ce:KNSBN crystal under a non-synchronous readout condition. The influence of the incident beam polarization state, intensity and incident angle on the beam fanning effect is studied with single beam incidence. The results show that when the beam has extraordinary polarization, the beam fanning effect is more evident and there exists an obvious intensity threshold of 38.2 mW/cm2. For a constant incident angle, the steady beam fanning intensity increases with the incident beam intensity. For a constant incident beam intensity, the steady beam fanning intensity increases with the incident angle to a peak value with 15° incident angle, and then declines with the rise of incident angle. The incident beam intensity threshold characteristic and the influence of the incident beam polarization state, intensity and incident angle on the steady beam fanning intensity are physically explained.