红外波片相位延迟的测试方法及精度分析

通过全面分析光强随波片方位角的变化从中优化出可适用于红外波段的确定波片延迟的方法。此方法只需读取输出光强的最大值和最小值,通过简单运算得到所测波片的相位延迟。以此为理论基础,建立了一套红外波片检测系统,此系统使用元件的数量较少,操作简单,重复性好,易于得到较高的测试精度。此外,从系统光源、光学元件到接收器件等组成部分分析了整个系统中各种误差源对测试精度的影响。结果表明,该系统的检测精度与波片延迟有关,并给出其关系曲线,由该曲线可知,当所测波片的延迟大于40ο时,该系统的仪器相对误差在1%之内,对于常用1/4和1/2波片,仪器相对误差分别为0.2%和0.01%。该检测系统的测试精度在可见和近红外波段基本保持不变。

Method and Precision Analysis for Measuring Retardation of Infrared Waveplate

A new method for measuring the retardation of waveplates in the infrared spectral region is derived by analyzing the light intensity variation with the azimuth angle. The phase retardations of waveplate are determined through reading out the maximum and minimum of light intensities and simple calculation. Based on this method, an instrument is set up to measure the retardations of the waveplates in the infrared range. With less devices, easy operation and sound repetition, measurement results with high precision are obtained. The effects on the measurement precision of the different sources, such as light source, polarizer and detector, etc., have been analyzed. It is found that the instrumental accuracy is related to the waveplate retardation, and their relation is plotted. From the plot it is found that the measurement precision is within 1% when the retardations of waveplates are more than 40°. The relative errors are measured to be 0.2% and 0.01% for the conventional quarter and half waveplates, respectively. The measurement precision of the system is almost constant in the visible and near-infrared range.