光学波片相位延迟测量仪设计

将光学波片放入激光谐振腔可使振荡模式发生分裂，测量分裂模的频率差能准确测得波片的相位延迟。基于这一原理，设计了光路沿竖直方向的相位延迟测量仪，可根据频率差不同引起振荡模式的变化采用相应测量方法。对半外腔激光器、光强和频差探测单元、控制程序等部分进行了设计说明。为了实现自动化和高精度测量，系统选定两正交偏振模的等光强点作为工作点，并补偿初始相位延迟和波片倾斜误差。测试表明，仪器能够对任意相位延迟的波片自动判定并测量，对多级波片多次测量的标准差约0.01，总的测量不确定度为0.03（优于/10 000），且只需要测量激光频率差，具有可溯源性。

Design of phase retardation measuring instrument for optical wave plate

One laser oscillating mode would split into two with an optical wave plate being inserted in the resonator. The frequency difference of splitting modes can be measured to obtain the wave plate phase retardation. Based on the principle, a measuring instrument for wave plate was designed with optical path along vertical direction, which could choose certain measuring method according to oscillating modes altered by frequency difference. The half-cavity laser, the detection of laser intensity and frequency difference, the controlling program were described in detail. In order to automatically measure wave plate with high precision, the instrument utilized the equal intensity point of two orthogonally polarized lights as working point, and compensated the systematic errors from initial phase retardation and slightly tilted wave plate. In testing experiments, the instrument can automatically discriminate and measure arbitrary retardance wave plates. The measurements show standard deviation of about 0.01 and uncertainty of 0.03 (less than /10 000) as to a multi-order quartz wave plate. The instrument has traceability and only the frequency difference of laser modes is acquired in measurement.