四区域法消除偏振棱镜缺陷对波片相位延迟测量的影响

在起偏器待测波片检偏器系统基础上提出一种四区域测量波片相位延迟量的方法。调整待测波片和检偏器的方位角,获得相应的四组光强值,通过线性运算得到待测波片的相位延迟量,完全消除了起偏器和检偏器不完全消光带来的误差。由于测量系统中不存在标准波片或其他相位调制元件,允许测量波长仅受偏振棱镜和探测器的限制,因此四区域法可适用于很大波长范围内的波片测量。以λ/4波片为例,理论分析了测量系统利用四区域测量法后的仪器误差为σ≤±3.49065×10-3rad(约0.2°),精度比原算法提高约1个数量级。实验验证了四区域法能有效提高系统精度。

Four-zone method to measure the phase retardation of wave plate is put forward based on the polarizer-wave plate-analyzer system. Four sets of light intensity were collected by adjusting azimuth angles of measured wave plate and analyzer. The phase retardation of the wave plate is figured out with linear calculation. This method eliminates the error caused by polarizer and analyzer imperfections completely in phase retardation measurement. No standard wave plate or other phase modulation instruments are necessary in the system. The measured wavelength range is extended, because it is only related to polarizing prisms and detectors. With this measuring system, the instrument error σ<inf>φ</inf> is less than ± 3.49065 × 10^-3 rad (about 0.2°). The accuracy is increased by about one order of magnitude compared with other algorithms which is verified by experiments.