8～14μm波段折衍混合红外光学系统的热补偿设计

大多数军用和空间光学仪器的工作环境温度变化范围都较大，温度变化时光学元件的曲率、厚度和间隔都将发生变化，同时元件基体材料的折射率及所在介质的折射率也将发生变化。由于红外光学材料的折射率温度系数dn／dT较大，环境温度对红外光学系统的影响显得尤为严重。因此在红外成像系统中不得不加入主动或被动补偿机构，以补偿温度变化造成像面移动所引起的系统性能的降低。利用衍射元件独特的温度特性实现红外光学系统热补偿设计的方法，设计了波段为8～14μm、视场为16。的折衍混合红外光学系统。该系统使用硒化锌和锗两种红外材料，在一40～60℃的温度范围内的成像质量接近衍射极限，并且体积小、结构简单，重量轻。

Design on Athermal Infrared Diffractive/Refractive Hybrid Optical System in 8～14 μm

Most optical instruments for military and aerospace application are expected to perform over a wide temperature range. The variation of the temperature will change the len's curvature, thickness and interval, as well as their refractive index and the refractive index of the surrounding. Because of the large temperature coefficient of the matcerial's refractive index, infrared optical systems often suffer from the performance degradation seriously. For this reason, several active or passive compensation mechanisms have to be appended to thermal imaging systems to compensate the performance degradation with temperature changes. Thermal properties of the refractive lens and diffractive lens are studied, and a method for designing athermal diffractive-refractive hybrid system in infrared region is introduced. An infrared diffractive-refractive hybrid optical system in 8～14 μm with 16°field of view is designed. In this system, two materials of Zinc selenide and Germanium are used, and the image quality of the system achieves diffractive limit at the temperature ranging from -20 ℃ to 60 ℃, with a compact structure and light weight.