折/反混合式长波红外成像光谱仪光学系统设计

为了实现遥感目标的长波红外高光谱成像，满足目标探测对多信息量的需求，设计了高光谱分辨率长波红外(8~12 μm)成像光谱仪。前置望远系统采用离轴三反系统，以实现无遮拦、大口径及宽视场成像设计；光谱分光系统分别采用折射式和反射式结构进行优化设计。设计结果显示，采用折射式结构，可得到通光孔径为100 mm，F数为2，光谱分辨率16 nm，空间分辨率150 μrad，冷光阑效率100%，成像质量接近衍射极限的光学系统；采用反射式结构，为了保证光学系统无挡光，需采用多片离轴反射镜，增加了系统的非对称性，使得系统的像散、彗差和场曲难以校正到最佳状态。设计结果表明：折/反混合式成像光谱系统具有光谱分辨率高、成像质量好和结构合理等优点，点斑均方根直径与国内现有探测器像素尺寸匹配。

Design of Hybrid Refractive and Reflective Optical System of Long-Wave Infrared Region Imaging Spectrometer

In order to achieve the long-wave infrared hyperspectral imaging for remote sensing target and to meet the needs of target detection for large amount of information, a long-wave infrared (8~12 μm) imaging spectrometer with high spectral resolution is designed. Off-axis three-mirror system is used in fore telescope system to implement a design of no obscuration, large diameter and wide-viewing-field imaging. The refraction and reflection structure is respectively used in optimizing the spectrophotometric system. The result shows that the optical system with an aperture of 100 mm, F number of 2, spectral resolution of 16 nm, spatial resolution of 150 μrad, cold aperture efficiency of 100% and image quality closing to the diffraction limit can be designed using refractive structure. However, when reflective structure is adopted, multi-chip off-axis mirrors are used to ensure that the optical system has no obscuration, which results in an increase of the asymmetry of the system and makes it difficult to correct the astigmatism, coma and field curvature to the best condition. The design result shows that hybrid refractive and reflective imaging spectrometer has the advantages of high spectral resolution, good image quality, reasonable structure and the match between the root-mean-square (RMS) diameter of point spot and the pixel size of the existing domestic detectors.