在旋转补偿器椭偏仪(RCE)的基础上,提出了一种自校准的波片相位延迟测量方法。该方法将补偿器的相位延迟作为未知参数,根据Mueller矩阵理论建立了4个非线性方程,求解得到待测波片的相位延迟;实现了补偿器相位延迟的自校准,消除了其定标不准确带来的系统误差,尤其适用于多个波长的波片延迟测量。在此基础上建立了一套波片延迟测量系统,并分析和模拟了各种主要的误差源对系统测量精度的影响。结果表明,对于任意延迟的波片,测量系统最大的系统误差和随机误差分别为0.036°和0.040°。此外,使用该方法分别测量了λ/4波片、λ/2波片、127°波片和空气(不放入任何样品)在波长517.3、525.0、532.4nm处的相位延迟以评估测量系统的性能,其中空气的相位延迟代表测量系统的测量精度,与模拟结果基本一致。
Based on the rotating-compensator ellipsometry(RCE),a method of phase retardation measurement of wave plates based on the self-calibration method is presented.The new method takes retardation of compensator as an unknown parameter,constructs four nonlinear equations,and calculates the retardation of wave plates under test.The method uses the self-calibration of compensator to eliminate the systematic error caused by its retardation′s inaccurate calibration.Especially,it is more convenient for retardation measurement in many wavelengths.Based on this,the measuring accuracy of system is analyzed and simulated.It is found that the maximal systematic error and random error are 0.036° and 0.04°,respectively,over all the samples.Besides,a quarter wave plate(QWP),a half wave plate(HWP),a 127° wave plate and the air(without sample) are measured at 517.3,525.0 and 532.4 nm,respectively,to evaluate the performance of the system,where the retardation of air indicates the measuring accuracy of the system,and is consistent with error analysis.