为了对偏振热成像系统进行定标, 设计了反射式红外可控部分偏振辐射源, 从理论计算和实验测量两方面进行对比论证.首先, 推导了铝反射镜的穆勒矩阵, 提出了辐射源出射辐射偏振态的理论计算方法, 结果表明, 能够产生线偏振度小于0.80、圆偏振度小于0.60的长波红外部分偏振辐射.然后, 基于铝反射镜搭建了部分偏振辐射源, 并用线偏振热成像系统对出射辐射的偏振态进行测量, 结果表明该辐射源可以产生线偏振度在0.25～0.85之间的长波红外部分偏振辐射, 当铝反射镜入射角低于80°时, 线偏振度测量值的相对标准偏差低于6%.

A reflection-mode controllable partially polarized infrared light source was designed to calibrate infrared imaging polarimeters. Theoretical calculation and measurement were carried out to verify the results. First, a theoretical calculation method was developed to calculate the polarization states of the output light based on the Mueller matrix of the aluminum coated flat mirror. Calculation results show that the output light is partially polarized with the degree of linear polarization (DoLP) smaller than 0.80 and the degree of circular polarization (DoCP) smaller than 0.60. Then a long wavelength infrared (LWIR) imaging polarimeter was employed to measure the real polarization states of the output light. Experimental results show that the output light is partially polarized with the DoLP within a range of 0.25 and 0.85 in LWIR. The relative standard deviation of DoLP is less than 6% when the incident angle for the flat mirror is less than 80°.