狭缝均质器型成像光谱仪光学设计

Optical Design of Slit Homogenizer Imaging Spectrometer

为提高星载成像光谱仪光谱数据保真度,抑制地面场景不均匀性造成的光谱失真,文章设计一种狭缝均质器型成像光谱仪光学系统,包括特定像散的前置望远系统、狭缝均质器和分光系统。通过狭缝均质器的引入,将实现匀化星载成像光谱仪中沿轨方向的景物光线,提高狭缝宽度方向照明均匀性,抑制光谱响应函数失真。设计结果显示:成像光谱仪通过四倍过采样采集光谱信息,弧矢方向MTF接近衍射极限;仿真成像光谱仪探测沿轨方向非均匀目标,其光谱响应函数失真值从传统成像光谱仪的42.8%降低至9.1%。该光学系统可有效抑制因观测场景不均匀造成的光谱失真现象,有利于成像光谱仪高保真的实现。

In order to improve the fidelity of the spectral data of the spaceborne imaging spectrometer and suppress the spectral distortion caused by the unevenness of the ground scene.In this paper,a slit homogenizer-type imaging spectrometer optical system is designed,which is composed,a front telephoto system with specific astigmatism,a slit homogenizer and a spectroscopic system.The introduction of the slit homogenizer will homogenize the light of the scene along the orbit in the spaceborne imaging spectrometer,improve the uniformity of illumination in the width direction of the slit,and suppress the distortion of the spectral response function.The design results show that the imaging spectrometer collects spectral information through four-fold oversampling,and the sagittal direction MTF is close to the diffraction limit;the simulated imaging spectrometer detects non-uniform targets along the orbit,and its spectral response function distortion value is reduced from 42.8%to 9.1%.The optical system can effectively suppress the spectral distortion caused by the uneven observation scene,which is beneficial to the realization of the high fidelity of the imaging spectrometer.