基于离轴两反利特罗结构的棱镜高光谱成像系统的光学设计

为满足高光谱成像系统高空间分辨率和高光谱分辨率的要求，并应对实际应用中对仪器小型化、轻量化、高光学效率的新需求，研究一种基于利特罗结构的棱镜色散高光谱成像系统，采用离轴两反的利特罗结构形式减小光学系统的体积，同时为平面棱镜提供准直光路，并以宏编程的优化方式，避免系统中光路干涉。结果表明，通过非球面反射镜和双校正透镜的设计，该光学成像系统的谱线弯曲均小于2.1 μm，色畸变小于1.3 μm，控制在18%像元内，在400～1 080 nm可见—近红外(VNIR)工作波段的光学调制传递函数(MTF)均达到0.9以上，光谱分辨率为1.6～5.0 nm，光谱透过率在51.5%以上，系统在整个工作光谱范围都具有较高的透过率和像质。

Study on the Design of Prism Hyperspectral Imaging System Based on Off-Axis Two-Mirror Littrow Configuration

In order to meet the requirements of high spectral resolution and high image quality on the hyperspectral imaging sys-tem,and to meet the new demands of miniaturization,light weight,and high optical efficiency in practical applications,a prism known as hyperspectral imaging system based on Littrow configuration is designed.The use of off-axis two-mirror Littrow con-figuration is to reduce the size of the optical system and provide a collimated beam for the plane prisms.To avoid the optical path interference,the macro programming optimization is applied.The application of two correct lens and aspheric mirrors can correct the spectral smile and the keystone of the hyperspectral imaging system.It is indicated that the distortion is less than 2.1μm and the spectral bend is less than 1.3μm,both are controlled within 1 8% pixel.The analytical results indicate that the MTF in the visible-near infrared(VNIR)spectral region from 400 to 1 080 nm is above 0.9 while spectrum resolution is about 1.6~5.0 nm, the spectral transmittance more than 5 1.5%.The results show that the system has high transmittance and image quality within the whole spectral range.