光学 精密工程, 2019, 27 (3): 533, 网络出版: 2019-05-30
大视场快焦比施密特系统在星载光谱仪中的应用
Application of Schmidt optical system with wide-field of view and fast focal ratio to aerospace imaging spectrometer
高光谱成像 施密特光学系统 非对称非球面 大视场 快焦比 imaging spectrometer Schmidt optical system axisymmetric anamorphic asphere large field of view fast ratio
摘要
根据大视场和快焦比空间遥感高光谱成像仪的研究目标, 采用折叠三反施密特望远镜和自由曲面Offner凸面光栅光谱仪结构, 设计了一个视场为5°, 焦比为2, 工作谱段在400~1 000 nm, 光谱分辨率为5 nm的星载高光谱成像仪光学系统。推导了非对称非球面施密特主镜的理论计算方法, 介绍了镜面的制造方法。利用Zemax光学设计软件进行了光线追迹和优化设计, 结果显示光谱畸变<0.88%, 光谱弯曲<1/3探测器像元, 所有谱段的光学传递函数均大于0.8, 满足星载高光谱成像仪的技术要求。施密特系统结构简单, 仅含有一个非球面, 在大视场工作时具有像质优良和畸变小的特点, 且中心遮拦比小、体积紧凑, 适合未来大视场快焦比的大口径星载遥感应用。
Abstract
To meet the application demands of a wide field of view and fast focal ratio for an aerospace imaging spectrometer, a three-mirror folded Schmidt telescope using a freeform Offner convex grating spectrometer was designed to obtain a field of view 5°, focal ratio of 2, spectral range of 400-1 000 nm, and spectral resolution of 5 nm for a space hyperspectral imager. The expression of an axisymmetric anamorphic asphere Schmidt surface was given and calculated, and a manufacturing method was introduced. The optical system for a Schmidt spectrometer was designed and optimized using software Zemax. Results show that spectral distortion is less than 0.88%, the spectral smile is smaller than 1/3 pixel size, and the optical module transfer function is greater than 0.8. These imaging characteristics can meet the requirements of a space imager. The Schmidt system shows a simple configuration and uses only a single aspherical mirror. Because it possesses excellent imaging specifications, small distortion, small central obscuration, and a compact size, Schmidt is the best candidate for a space instrument with a large aperture, large field of view, and fast focal ratio.
王欣, 刘强, 舒嵘. 大视场快焦比施密特系统在星载光谱仪中的应用[J]. 光学 精密工程, 2019, 27(3): 533. WANG Xin, LIU Qiang, SHU Rong. Application of Schmidt optical system with wide-field of view and fast focal ratio to aerospace imaging spectrometer[J]. Optics and Precision Engineering, 2019, 27(3): 533.