基于微透镜阵列的积分视场成像光谱仪前置成像系统分析与设计

作为对天文光谱进行观测的仪器，成像光谱仪有着十分重要的作用。由于传统的狭缝型成像光谱仪的狭缝限制，对面源天体的观测需多次扫面，才能获得完整的面源三维数据立方体(x, y; λ)，这样将会浪费大量的观测时间。为了实现目标物体三维数据立方体的快速扫描，提出了一种基于微透镜阵列的无狭缝、静态化、快速高效的可见光到近红外波段积分视场成像光谱仪结构，并对其基本工作原理进行分析。为了扩展微透镜阵列积分视场成像光谱仪在医学、农业、物探等其他领域的应用潜能，该研究的光谱波段选择可见光到近红外波段。根据视场积分的工作原理，分析和设计了像方远心结构的离轴三反前置成像系统。系统采用视场离轴方式，波段范围400～900 nm，相对口径F/5，主镜、次镜和三镜皆为二次非球面，二次非球面系数分别为：-7.05，-0.92和-1.61。为减小系统体积，在离轴三反系统的焦平面附近放置反射镜。系统在奈奎斯特空间频率60 lp·mm-1处，调制传递函数大于0.75，成像质量接近衍射极限，满足系统要求。

Analysis and Design of Pre-Imaging System of Integral Field Imaging Spectrometer Based on Lenslet Array

As an instrument for observing astronomical spectroscopy, imaging spectroscopy plays a very important role. Due to the slit limitation of the traditional slit type imaging spectrometer, the observation of the surface source object needs to be scanned several times in order to obtain the complete three-dimensional data cube (x, y; λ), which will waste a lot of observation time. In order to realize the fast scanning of the three-dimensional data cube of the target object, this paper presents a micro-lens array with no slit, static, fast and efficient visible-to-infrared band integral field imaging spectrometer structure, and analyses its basic working principle. In order to expand the application potential of spectrometer in medicine, agriculture, geophysical prospecting and other fields, the spectral bands selected in this paper ranged from visible to near infrared. According to the working principle of field integration, the off-axis three-reverse imaging system is analyzed and designed. The system uses the field of view from the off-axis mode, the band range is 400～900 nm, relative diameter is F/5. Primary mirror, secondary mirror and three mirrors are all secondary aspherical mirrors, the second aspheric surface coefficients are -7.05, -0.92 and -1.61, respectively. In order to reduce the system volume, the mirror is placed near the focal plane of the off-axis three-reaction system. In the Nyquist space with the frequency of 60 lp·mm-1, the modulation transfer function is greater than 0.75, the image quality close to the diffraction limit. These parameters all meet the system requirements.