消谱线弯曲棱镜-光栅型成像光谱仪设计

Design of Prism-Grating Imaging Spectrometer with Eliminating Spectral Line Curvature

针对平面光栅和棱镜成像光谱仪难以校正谱线弯曲的问题,提出了利用棱镜-光栅(P-G)组合分光元件并结合系统物镜畸变校正谱线弯曲的方法。分别计算了棱镜和光栅产生的谱线弯曲以及P-G组合元件产生的光谱弯曲,分析了棱镜和光栅的谱线弯曲特性,并基于此设计了P-G组合分光元件和消谱线弯曲成像光谱仪结构。通过优化设计得到光学系统的光谱分辨率高于2nm,点列图均方根(RMS)半径小于8μm,系统谱线弯曲和光谱弯曲小于2μm。证明了P-G组合元件结合系统物镜畸变可补偿校正整个工作波段的谱线弯曲和光谱弯曲。最后的设计结果表明,基于P-G分光元件的成像光谱仪系统在满足像质要求的前提下,谱线弯曲小于1/4像元尺寸,满足使用要求。

In order to eliminate spectral line curvature of plane grating and prism imaging spectrometer, a novel approach by combining prism-grating （P-G） with the compensation of lens＇ distortion is presented. The spectral line curvatures of prism and grating and spectral curvature of compound P-G device are calculated, respectively. The character of spectral line curvature and spectral curvature are analyzed, then the compound P-G device and imaging spectrometer with eliminating spectral line curvature are designed. The optimized optical system has a spectral resolution better than 2 nm and the root mean square （RMS） spot radius is less than 8 μm. Moreover, both the spectral line curvature and spectral curvature of system are less than 2 μm. It is proves that compound P-G device＇s spectral line curvature and spectral curvature of the full-wide working wavelength can be eliminated with the compensation of lens distortion. It is concluded that the imaging spectrometer with P-G dispersing device shows a spectral line curvature less than 1/4 pixel of the detector, which meets the use request on the premise of imaging quality.