基于菲涅耳公式，分析了偏振光通过钕玻璃片的透射率及反射率，讨论了高功率固体激光装置离轴光束对隔离性能的影响。根据光轴和小开关晶体晶轴走偏导致的退偏损耗的原理，可以使用开关晶体的姿态去补偿光束旋转误差的退偏损耗。实验结果表明，钕玻璃片小角度变化不影响系统对偏振光选择性通过，并且利用开关晶体来补偿光束旋转误差的退偏损耗能提高系统隔离比3倍以上。

The transmissivity and reflectivity of polarized light through Nd-glass are analyzed based on the Fresnel formula. The influence of the off-axis light in high power solid-laser facility on the isolation performance of main-amplifier system is discussed. The attitude of crystal in the small electro-optical switch is adjusted to compensate the depolarization loss due to beam rotating error, according to the mechanism that the off-axis light through the crystal of the switch will result in depolarization loss. Experimental results indicate that the system selectivity towards polarized light is not influenced by the small angle change of Nd-glass, and the isolation rate of main-amplifier system can be improved more than three times through the attitude adjustment.