基于磁光调制及基频信号检测的高精度波片测量

为提高波片相位延迟量的准确性，提出了一种基于磁光调制的波片相位延迟量测量方法.在标准1/4波片和检偏器之间插入磁光调制器，调整元件转角使出射光强只剩下偶次谐波成分，利用该特性，通过检测基频成分的残余量而非整个光强信号来进行波片相位延迟量的精密测量.利用琼斯矩阵推导了相应的理论公式并建立了波片测量系统，误差分析表明当环境温度变化范围为0.1℃时，系统测量不确定优于5'，对1/2波片和1/4波片的重复测量实验表明测量标准偏差约为2'. 

A Wave Plate Measurement Method Based on Magneto-Optical Modulating and Base Frequency Signal Detecting

To improve the accu racy of phase retardation measurement, a wave plate measurement method was proposed based on magneto-optical modulating and base frequency signal detecting. Firstly, a magneto-optical modulator was placed at a suitable location of the optical path to be adjusted and to make only even harmonic components be left in the measurement signal. And then, detecting the residue of the base frequency component instead of whole spectrum signal, the phase retardation measurement of wave plate was carried out accurately. Finally, the theoretical formulae and corresponding wave plate measuring system were established based on Jones matrix. The analysis results show that, when the ambient temperature changes 0.1°, the measurement uncertainty of the system can be less than 5''. Half-wave plates (HWP) and quarter-wave plates'' (QWP) measurement results show that, the measurement standard deviation is about 2''.