空间高层大气遥感远紫外成像光谱仪的光学系统

空间高层大气遥感远紫外成像光谱仪主要用于观测高层大气中的远紫外辐射和实现对其内部中尺度现象成像的功能。目前我国该类的相关仪器研究基础还比较薄弱,针对这种情况,在光学系统设计的角度上给出了一种适用于130～180nm波段探测的光学系统方案。该成像光谱仪光学系统以离轴抛物镜为物镜,串联Wadsworth结构为成像光谱系统;这种串联Wadsworth成像光谱系统采用离轴抛物镜做准直镜,分光器件为平面光栅和球面光栅串联,实现二次色散,同时球面光栅起到聚焦成像作用;在像差理论的基础上,对该结构的光程函数和各像差进行了分析,获得了改进结构的宽波段完善成像条件。针对低轨空间探测应用要求设计了相关改进型Wadsworth结构成像光谱仪光学系统,设计结果证明系统像差得到了充分校正,在奈奎斯特频率(20lp/mm)下全视场全波段调制传递函数值在0.6以上。该优化结构同时具备高空间分辨率和高光谱分辨率,性能优越。

Optical System of Far Ultraviolet Imaging Spectrometer for Space-Based Upper Atmosphere Remote Sensing

Far ultraviolet imaging spectrometer for upper atmosphere remote sensing is mainly used in observation on the far ultraviolet radiation and imaging for the mesoclimate phenomenon in the upper atmosphere. The foundation of correlated instruments is still frail in our country. A program in optical design is presented to improve the study of the imaging spectrometer for far ultraviolet observation in 130~180 nm. It is composed of the telescope with an off-axis parabolic mirror and the imaging spectrum system structure with tandem Wadsworth system. The tandem Wadsworth spectral imaging system adopts the collimator as an off-axis parabolic mirror. The light splitting device consists of a plane grating and a concave grating. The structure can realize quadrate dispersion. And the concave grating is used for focusing and imaging. Based on the aberration theory, the optical path function and aberration coefficients of the system are analyzed, and perfect imaging conditions of the improved structure are obtained. A design example using the perfect conditions is designed to meet the requests of the application in space observation in low orbit. The results demonstrate that the aberrations of the system are substantially corrected, and the modulation transfer functions in total fields of view and all waveband are more than 0.6. The improved structure is more convenient. The space resolution and the spectral resolution are both high.