采用旋转波片法搭建了一套偏振态斯托克斯参量自动检测系统,每秒可以处理和显示15个偏振椭圆。该系统采用数据采集卡和LabVIEW软件来组成虚拟仪器,通过数据插值与重采样技术对旋转角度进行精确定位,消除了电机转速不稳定带来的系统误差。根据米勒矩阵得出透射光强随旋转角度的变化方程,并与实时采集的测量数据进行对比拟合,通过傅里叶变换得出曲线方程中的待定系数,给出对应的斯托克斯参量,并计算光波的电场分量及相位差,确定出射光的椭圆偏振消光比、长轴方向与椭圆旋向。还考查了本底噪声对测量结果的影响,比较了旋转波片与旋转检偏器两种测试方法的优缺点。

By the method of rotating quarter-wave plate,an automatic measurement system for the Stokes parameters of polarization state has been set up. It can process and display 15 polarization ellipses per second. The virtual instrument in this system consists of a data acquisition card and the LabVIEW software. The rotating angle is determined precisely by data interpolation and resample,so that the systematic error caused by the instability of rotating motor is depressed. The variation equation of transmitting light intensity with the rotating angle is deduced theoretically by Mueller matrix. The real-time acquired data is compared and fitted with the analytic equation. The coefficients of the variation equation and the correspondent Stokes parameters are given by Fourier transform. The field components and their phase difference of light wave are calculated. The distinction ratio,long axis orientation and spin-wise of polarization ellipse are determined. The influence of background noise on the measurement result is examined. The performances are compared between the two methods of rotating wave-plate and rotating analyzer.