宽谱段共光轴线色散成像光谱仪三棱镜分光系统设计

摘要

To overcome the difficulties of complex structure and serious nonlinear dispersion in prismatic imaging spectrometer the coaxial linear dispersion prismatic imaging spectrometer is investigated in this paper.A mathematical model of symmetric tri-ple prisms’beam splitting system is constructed with prism's dispersion equation,and the prisms assemble of direct view is ob-tained.Then the factors affecting dispersion linearity are analyzed.The refractive index and dispersion rate of prism material im-pact dispersion linearity most while the influence of incident angle is very small.The way to improve dispersion linearity is given and the refractive index condition meeting the requirement of dispersion linearity of prisms is obtained.It provides important ba-sis to select the initial structure for coaxial linear dispersion triplet prisms of imaging spectrometer.On condition that the work-ing band of 400~1 000 nm,center wavelength deviation angle 0°,the maximum dispersion angle 0.6°,object numerical aperture 0.1 5 and spectral resolution 5 nm,we succeed in designing coaxial linear dispersion triplet prisms.Digital simulation with ZEM-AX is performed,and the results are in accordance with theoretical analysis.%针对棱镜型成像光谱仪结构复杂、具有严重的色散不均匀性，进行了共光轴线色散棱镜式宽谱段成像光谱仪研究。利用棱镜的色散公式建立了对称型三棱镜组合分光结构的数学模型，获得了满足直视结构的棱镜组合，并在此基础上分析影响棱镜组色散线性因素：棱镜材料的折射率和色散率对棱镜组线色散影响比较大，入射角度对其影响比较小，并提出改善色散线性的方法，获得了满足线色散要求的棱镜组合的折射率条件，从而为共光轴结构的线色散棱镜式成像光谱仪初始结构的选择提供了重要理论依据。在工作波段为400~1000 nm、中心波长偏向角为0°、最大色散角为0.6°、光谱仪系统数值孔径 NA为0.18、光谱分辨率为5 nm条件下，实现共光轴三棱镜分光系统的线色散设计，最后利用 ZEMAX 进行了模拟分析表明，理论计算结果与实际仿真结果基本相符。