宽谱段改进型Wadsworth光栅型成像光谱仪光学设计

Optical Design of Broadband Advanced Wadsworth Grating Imaging Spectrometer

针对传统的Wadsworth光学系统无法应用于宽谱段高分辨率成像光谱仪的情况,给出了一种改进的光学系统方案。通过在Wadsworth系统中加入柱面镜的方法,改变了子午和弧矢方向成像聚焦距离。在对像散和光程分析的基础上,计算获得了改进型Wadsworth成像光谱仪光学系统的最优成像条件,即柱面镜的最优放置位置、最优倾斜角和最优楔角。以一个工作波段为400～800nm的改进型光学系统设计实例,对设计理论进行了验证。设计结果表明系统具备良好的光学成像质量,探测器在奈奎斯特频率（20lp/mm）下全视场全波段调制传递函数值达到0.57以上,光谱分辨率达到1.6nm,实现了对Wadsworth系统的有效改进。

An advanced optical system has been obtained to solve the problem that the traditional Wadsworth optical system can not be applied for broadband imaging spectrometer with high resolution. The meridian and sagittal focal lengths have been changed by the method of adding a cylindrical lens into the Wadsworth optical system. The optimal imaging conditions including location, inclined angle and wedge angle of the cylindrical lens have been calculated based on the analysis of the astigmatism and optical path. An example of the advanced optical system design with the working waveband of 400 - 800 nm has been presented to verify the theory. The results present good optical performances of the advanced system. The modulation transfer functions in all fields of view and working waveband are over 0.57, and the spectral resolution is 1.6 nm. The Wadsworth system is improved effectively.