中波红外傅里叶变换成像光谱仪后置成像系统分析与设计

Design and Analysis for the Rear Imaging System of a Medium Wave Infrared Fourier Transform Imaging Spectrometer

提出了一种基于多级微反射镜的静态化新型红外傅里叶变换成像光谱仪结构。系统不含狭缝和可动部件，因此光通量大、结构稳定。介绍了该成像光谱仪的工作原理和光程差的产生方式。根据系统原理对后置成像光学系统进行了分析与设计。结果表明：在-20℃～60℃的温度范围内，系统成像质量良好。全视场传递函数在CCD奈奎斯特频率17lp／mm处大于0．6。系统的均方根（RMS）最大光斑直径小于12μm，系统单个像元能量集中度大于80％，冷光阑匹配效率接近100％。以RMS光斑直径变化为标准，计算了系统的公差灵敏度矩阵，计算结果表明，后置成像系统0视场光斑尺寸小于16μm的可能性为97．7％。

A novel static infrared Fourier transform imaging spectrometer based on the multi-level micro-mirrors is proposed. The system does not contain slit and moving parts, thus the system has the advantages of a large luminous flux and a stable structure. The working principle and the generating means of the optical path difference for the imaging spectrometer are introduced. According to the working principle of the system, the rear imaging system has been analyzed and designed. The designed results show that the rear imaging system has a fine image quality at the temperature range of -20 ℃ ~ 60 ℃. In the full field of the Nyquist frequency of 17 lp/mm, the modulation transfer function （MTF） of the rear imaging system is greater than 0. 6. The maximum root mean square （RMS） spot diameter of the system is less than 12 μm. The single pixel energy concentration is greater than 80 % and the cold stop matching efficiency is near 100%. The changing of the RMS spot diameter as the standard is used to calculate the tolerance sensitivity matrix and the result shows that in the zero field the probability of spot diameter less than 16 μm is 97.7%.