Offner型消热差中波红外成像光谱仪设计

Design of athermal mid-infrared imaging spectrometer based on Offner scheme

为了满足中波红外光谱分析的需要,设计了Offner型中波红外成像光谱仪。在分析红外系统消热差方程的基础上,明确通过选择不同热特性材料的合理组合可以设计出合理的消热差光学结构;在分析Offner结构原理的基础上,建立了一种简化的初始结构求解过程以及采用光学仿真软件进行优化的设计方法。最后,利用该方法设计了工作波段为3~5μm的推扫式成像光谱仪,并进行了一体化消热差设计,工作温度范围为-40~100℃,全视场范围内的弥散斑小于30μm,调制传递函数值在空间截止频率16.7 lp/mm处均大于0.35,光谱分辨率小于15.6 nm,具有较好的光谱分光性能。

An athermal mid-infrared imaging spectrometer based on the Offner scheme was designed to meet the requirement of mid-infrared spectrum analysis. According to the solution of the athermal equations, athermal structure could be designed reasonably through reasonable combination of materials with different thermal properties. Method of solving the initial structure and optical software optimization was introduced based on the analysis of Offner structure principle. A push broom imaging spectrometer with 3-5 μm spectral range was designed by this method, and its operating temperature range is from-40 ℃ to 100 ℃ depending on the achromatic optimization. The spectrometer has good spectral performances, the dispersion spot diameter of which is less than 30 μm in the full field of view. The spectrometer′ s transfer function value is greater than 0.35 at the spatial cutoff frequency of 16.7 lp/mm,and its spectral resolution is less than 15.6 nm.