对离轴光线通过电光晶体时产生的退偏情况作了理论和实验研究.理论计算表明:当晶体厚度一定时,退偏损耗在一定范围内随离轴角度的增加而增加,随着入射光偏振方向偏离竖直方向的增大而增大.采用厚度为10mm的KDP晶体,实验测试了入射光偏振方向在竖直方向以及同竖直方向成45°时的退偏损耗.实验结果与理论计算的结果符合较好.

The relation between the angle of off-axis-light and the depolarization loss has been calculated under different incidence of polarization. The results show when the thickness of crystal was settled, the depolarization loss is directly proportional to the angle of off-axis-light and the angle between the polarization of laser beam and the main axis of crystal in some confine. When the thickness of crystal is 10mm, the depolarization loss under different case was measured. When the angle of off-axis-light is less than 15mrad, the depolarization loss of electro-optical crystal is less than 0.5%, but when the angle is larger than 15mrad, the depolarization increases very quickly. The measurement results are in accord with ones of the calculation.