热红外成像光谱仪广泛应用于工业研究、环境监测以及自然资源探测等多个领域。随着大面阵红外探测器技术的发展，大视场大相对孔径热红外光谱仪已成为遥感领域新的发展方向。本文介绍了一种基于凸面光栅的同轴Offner 结构，对常规Offner 结构进行改进，仅使用一块大凹面反射镜，在凸面光栅的位置插入带有负像散的校正透镜。设计验证结果表明，这种结构在热红外波段具有非常优异的表现，较传统Offner 结构能实现更大的视场，更小的F 数。最后利用这种结构设计了60 mm 狭缝视场，F 数为2 的热红外光谱仪，其成像弥散斑直径小于5 mm，MTF 达到衍射极限。该热红外光谱仪系统结构紧凑，非常适合航天航空遥感的应用。

Thermal infrared imaging spectrometer can be widely used in industrial research, environment monitoring, and detection of natural resources. With the development of large-array infrared detector, wide field and large relative aperture thermal infrared spectrometer becomes a new direction. The purpose of this paper is to introduce an improved coaxial Offner system with convex grating just with a large piece of concave reflector and inserting a correction lens with negative astigmatism in the position of the convex grating. The analysis shows this structure can realize a larger FOV and smaller F number in thermal infrared band. A system with 60 mm slit and F/# 2 which uses this structure gets high imaging quality, of which disc of confusion is less than 5 μm and the MTF reaches diffraction limit. The compact spectrometer system is very suitable for aviation and space remote sensing applications.