谐衍射中、长波红外超光谱成像系统设计

为了充分利用中波红外和长波红外的光谱信息,建立了谐衍射中、长波红外超光谱成像系统。利用谐衍射元件独特的色散特性,将谐衍射透镜应用于中、长波红外超光谱成像系统中,使系统在中波红外3.7~4.8μm和长波红外8.5~12μm的2个谐振波段内获取二百多个不同波长的图像信息。设计结果显示,在中波红外波段18lp/mm处,光学调制传递函数0.52;长波红外波段13lp/mm处,光学调制传递函数0.51;光学系统的点斑均方根直径在中波红外波段小于27μm,在长波红外波段小于34μm。得到的结果表明,光学调制传递函数在各个波长处均接近衍射极限,点斑的均方根直径完全可以与国内现有探测器的像元尺寸匹配。

Design on hyper-spectral imaging system with harmonic diffraction element in medium and long infrared

Objective: In order to get enough information, make the best of the spectral information of medium and long infrared, this article establishes a harmonic diffractive / refractive optical system in middle and long infrared. Method: In this paper, the hyper-spectral imaging system in medium and long infrared has obtained more than 200 spectral images, during medium-wave infrared band 3.7-4.8µm and long-wave infrared band 8.5-12µm, based on the special large dispersion capability of harmonic diffractive element. Result: The design results show that the design: at 18 lines/mm, the optical modulation transfer function is greater than 0.53 in medium-wave infrared band; at 13 lines/mm the optical modulation transfer is greater than 0.51 in long-wave infrared band; the RMS spot diameter is less than 30 in medium-wave infrared band and less than 37 in long-wave infrared band. Conclusion: The optical modulation transfer function at all wavelengths are close to the diffraction limit; and point of the RMS spot diameter can match with the existing detector pixel size.