介绍了一种新的判断波片快轴方位的方法。 根据波片相位电光补偿测量原理， 采用叠加固定频率的交流电压调制信号， 获得偏振消光系统输出信息与调制信号间的关系。 利用琼斯矩阵对这一过程进行分析发现， 输出光信息通常情况下是由基频和倍频信息叠加而成， 叠加结果不仅反映了波片的相位信息， 而且反映了波片的轴向信息。 通过对此现象的深入分析研究， 得到了不同方位放置的波片经旋转后导致的叠加波形形状的变化趋势， 通过观察这种变化趋势， 能够非常容易地判定相位延迟＜π或＞π波片的快轴和慢轴， 相位延迟＜π或＞π波片导致的现象相反。

A new method for the determination of fast axis of wave-plate is introduced. Based on the principle of electro-optic phase compensation in the wave-plate phase measuring method, the relation between the polarization extinction system out-put signal and the modulating signal can be acquired through the composition of frequency fixed alternating voltage modulation signal. Through the analysis of this process with Jones matrix, the out-put signal was usually found to be the composition of fundamental frequency and second harmonic frequency, the composition signal reflects the axis information as well as the phase information of the wave-plate, and this phenomenon has never been noticed before. Through the analysis of this phenomenon, the transformation trends of the composed wave-form by rotating of wave-plates with different orientations were deduced, and through the observation of the transformation trend, one can easily distinguish the fast and slow axes of wave-plates with phase retardation >π as well as those with phase retardation <π, and their phenomena are reverse to each other.