为了精确测量光相位器的延迟量,提出了一种新的测量方法,并利用米勒矩阵理论分析了影响测量结果的因素。测量系统主要由起偏棱镜、标准四分之一波片、检偏棱镜、锁相放大器和微处理器构成。该方法利用最小二乘算法得到了最优傅里叶系数,利用锁相放大器的窄带滤波作用提高了信噪比,利用反馈环控制系统对步进电机的步进角进行了控制。误差分析表明这一方法的绝对误差小于0.29°,对四分之一石英波片相位延迟量进行了实验测试,结果表明其重复测量误差小于0.40°。

In order to measure the retardation of phase retarders accurately, a new method is presented, the errors influencing test results are studied by Müller matrix theory. The measurement setup is composed of polarizing prism, normal quarter-wave plate, analyzing prism, lock-in amplifier and microprocessor. The best Fourier coefficients of the signal are obtained by the least squares method. By the band-limited functions of the lock-in amplifier, the signal-to-noise ratio is improved. A high-accuracy step motor is used to control the rotation angle by the feedback loop system. The theoretical analysis of error proves that the absolute error is less than 0.29°. The retardation of a normal quarter-wave quartz plate is measured with repetitive error less than 0.40°.