AOTF与中阶梯光栅结合的小型化超光谱分辨率成像光谱仪  

Miniaturized Hyperspectral Resolution Imaging Spectrometer of AOTF and Echelle Grating Combination

作　　者：张磊[1,2] 李博 顾国超[1] 王晓旭[1] 李寒霜[1] Zhang Lei;Li Bo;Gu Guochao;Wang Xiaoxu;Li Hanshuang(Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,Jilin,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所,吉林长春130033 [2]中国科学院大学,北京100049

出　　处：《光学学报》2023年第19期249-256,共8页Acta Optica Sinica

基　　金：地球绝对光谱辐亮度测量基准载荷工程技术(2022YFB3903202)。

摘　　要：对传统中阶梯光栅光谱仪级次重叠的问题进行分析,采用声光可谐调滤波器(AOTF)结合中阶梯光栅的方法实现光谱级次分离,研究并设计了小型、灵敏、超高光谱分辨率的光学系统结构。利用CODEV软件对成像光谱仪的初始结构进行优化,得到一种结合AOTF与中阶梯光栅的小型化超高光谱分辨率成像光谱仪。与交叉色散方案相比,中阶梯光栅与AOTF结合的技术将得到更高的信噪比,并弥补了中阶梯光栅体积大、质量重的缺陷,工作波段在2320~4250 nm时,系统F数小于1.8,并获得优于0.15 nm的超高光谱分辨率,在奈奎斯特频率为17 lp/mm条件下整体调制传递函数(MTF)>0.7,各视场全波段弥散斑均方根(RMS)半径<11μm。该成像光谱仪提供了一种大气微量成分高精度、高灵敏度测量的方案,与其他的高分辨率红外光谱仪相比,其更容易安装在空间资源有限的行星或星际航天器上。Objective A variety of infrared spectrometers have been designed in China and abroad to achieve sensitive and highresolution measurement of the absorption spectrum of trace components in the atmosphere,but the spectral resolution is relatively low,which seriously hinders the detection of tiny species in the atmosphere.Because of its special dual dispersion structure,the echelle grating can realize both wide-band and high-resolution spectral measurement.However,the spectrum order overlap of the echelle grating is serious and should be combined with secondary dispersion elements to eliminate the order overlap.As a result,the optical system structure is complicated,with large weight and too high processing cost.Therefore,it is necessary to improve the optical system structure to make the spectrometer easier to employ on the spacecraft and ensure imaging quality.Methods We improve the traditional echelle grating spectrometer system,and study and design a small,sensitive,and ultra-high spectral resolution optical system structure.The structure adopts an acousto-optic tunable filter(AOTF)combined with echelle grating to achieve spectral order separation.AOTF is made according to the acousto-optic diffraction principle of birefringent crystal.Compared with the prism or grating in the traditional spectral analysis system,AOTF features small volume,light weight,arbitrary wavelength selection,and high diffraction efficiency.Due to the aperture limitation of AOTF,the beam enters AOTF after being collimated by the beam reduction system,and the spectral information of each spectrum segment is obtained in the image plane after the beam is spliced through the echelle grating.Finally,the optimized telescopic system and the spectrometer are interfaced to obtain the overall optical structure of the hyperspectral resolution imaging spectrometer,and the slit overlaps with the image plane of the telescopic system.According to the grating equation,different diffraction levels need to be adopted to make the corresponding wavelength of

关 键 词：光学设计 成像光谱仪 AOTF 中阶梯光栅 

分 类 号：TH744[机械工程—光学工程]