时空联合调制成像光谱仪前置成像系统分析与设计

Design and analysis for the front imaging optical system of the spatiotemporal mixed modulated Fourier transform imaging spectrometer

为满足红外成像光谱仪大光通量、高稳定性的应用需求,提出了一种基于多级阶梯微反射镜的静态化、无狭缝式、新型红外时空联合调制型傅里叶变换成像光谱仪结构.对其工作原理和光程差的产生方式进行了分析.作为该成像光谱仪的重要部件,前置成像系统决定了光程差的分布,其性能直接影响到目标物体的图像质量.根据系统光程差的产生方式,分析和设计了像方远心光路结构的前置成像系统.利用被动光学消热差方法对前置成像系统进行了消热差研究.结果表明:当温度在-20—60?C的范围内时,各个视场的调制传递函数均达到衍射极限,在多级阶梯微反射镜的总阶梯高度范围内成像质量良好;在不同的温度下,各视场处主光线在像面上的最大入射角小于0.02?.

In order to satisfy the application requirements of the large flux and the high stability for the infrared imaging spectrometer, we propose a new type of static no-slit spatiotemporally mixed modulated Fourier transform imaging spectrometer based on the multi-level micro-mirrors. The working process and the generation manner of optical path difference of the system are analyzed. The front imaging system, as an important component of the imaging spectrometer, determines the distribution of the optical path difference, and its performance directly affects the image quality of target object. According to the generation manner of optical path difference of the system, the front imaging system for the telecentric structure in the image space is analyzed and designed. The athermalization design research is carried out by means of the passive optical elimination thermal difference. The result shows that the modulation transfer function curve of each field reaches the diffraction limit in a temperature range of -20-60℃. The front imaging optical system has a good imaging quality in the total step height of the multi-step micro-mirrors. At different temperatures, the maximum incident angle on the image surface is less than 0.02° for the principal ray of each field.