中波红外折衍光学系统消热差设计与杂光分析

MWIR refractive /diffractive hybrid athermal optical system and its stray light analysis

论述了红外折衍混合消热差光学系统的设计原理与方法,利用衍射光学元件特性进行消热差与色差,设计出工作波段为3.5μm^5.2μm、F数为2、焦距为100 mm、全视场角7,°具有100%冷屏效率的折衍混合消热差光学系统。对系统进行杂光分析,理想成像光线的像面辐照度为1.5×104W/m2,其他非成像光线的像面辐照度为2 W/m2。该系统在-50℃~80℃的温度范围内成像质量接近衍射极限,适用于像元尺寸为30μm、像元数320×256的致冷型红外焦平面阵列探测器。

The concept and design of infrared hybrid diffractive/refractive athermalized optical system are described.A diffractive optical element is used to athermalize and achromatize the optical system.A hybrid optical system operating at 3.5 μm～5.2 μm wave band and the temperature range of-50～80℃ is designed.The system parameters include a focal length of 100 mm,F/# 2,and FOV of ±3.5°,and it achieves 100% cold shield efficiency.The system stray light is analyzed,and the irradiances of the desired light and the stay light are 1.5×104 W/m2 and 2 W/m2 respectively.The image quality achieved in the temperature range of-50℃～80℃ approaches the diffraction limitation.It is applicable to a cooled FPA detector with the format of 320×256 and the pixel pitch of 30 μm.