中国科学院云南天文台机构知识库

大口径太阳望远镜中常用波片来进行偏振定标和偏振测量,为了对这类波片的延迟量和方位角进行准确测量,提出一种基于双光束检偏的波片测量系统,建立了该系统对应的数学模型。测量系统中检偏器的方位角可作为参数进行拟合,克服了单光束测量系统中检偏器方位角误差的影响;同时,根据测量系统的结构,对待测波片的延迟量范围进行分析,实现了对偏振定标和偏振测量中所使用波片的精确测量。分析了测量系统误差的主要来源,包括光源光强噪声、电机定位误差和探测器非线性响应,并对探测器非线性响应进行了校正。该方法测量1/4波片和127°波片的延迟量和方位角误差小于0.02°,测量27°～145°和215°～333°范围波片样品的延迟量和方位角误差小于0.05°。 

A wave plate is commonly used for polarization measurement and polarization calibration of a large solar telescope. In this study, we developed a measurement system based on the dual-beam polariztion analyzer configuration to measure the phase retardance and azimuth angle of the wave plate, and derived the corresponding mathemantical model. The influence of azimuth error of the polarizerin the single bema measurement system was overcome by fitting the azimuth of the polarizer. At the same time, we analyzed the retardance range of the measuring plate, and accurately measured the wave plate used in polarization calibration and polarication measurement. Finally, we analyzed the main error sources of the system, including the power noise of the light soucec, position error of the rotating stage, and nonlinear response of the detector. Sunbsequently, we corrected the detector/s nonlinear response after calibration. The measurement errors of phase retardance and azimuth angle are within 0.02^。 for a quater-wave plate and a wave plate with pase retardaces of 127^。. The retardance and azimuth errors are leass than 0.05^。 for the wave plates with phase retardances of 27^。-145^。 and 215^。-333^。.