星载高分辨率超光谱成像仪分光方式的选择

Choice of spectral-splitting modes in space-borne hyper-spectral imager

从透光率、光谱范围杂散光、可靠性、色散线性、光谱带宽、成本等多个方面分析了超光谱成像光谱仪采用棱镜或光栅色散分光的优缺点。分析显示,棱镜光谱仪透过率高达95.24%(VNIR),而光栅的衍射效率仅为60%～70%。棱镜光谱仪的杂散光可达10-4,而光栅的杂散光为10-2。尽管光栅光谱仪的波长覆盖范围要比棱镜光谱仪好,但在0.4～2.5μm,棱镜光谱仪相对光栅光谱仪有优越性。此外,光栅光谱仪的色散基本为线性,但棱镜光谱仪的短波非线性问题可通过复合棱镜进行补偿,而且,棱镜光谱仪的可靠性好于光栅光谱仪。另外,两种光谱仪的光谱带宽和成本基本接近。这些结果表明,棱镜更适于星载高分辨率超光谱成像仪的分光。

This paper analyzes the advantages and disadvantages of two kind of splitting modes, prism splitting and grating splitting, from different points of view. The analysis indicates that the transmission efficiency of the prism spectrometer is 95.24% （VNIR） and the diffraction efficiency of the grating spectrometer is between 60% and 70%. Moreover, the stray light of the prism spectrometer is 10-4 and that of the grating spectrometer is 10-2. Furthermore, the spectral covering ability of the sprism spectrometer is better than that of the grating spectrometer from 0. 4 - 2. 5 Ixm, although the latter has a good spectral working region. In the dispersion linearity aspect, the grating spectrometer are linear, but the nonlinear problem of shortwave for the prism spectrometer can be solved through a composite-prism. In addition, the prism spectrometer is more reliable than the grating spectrometer, but both the spectrometers are equivalent in the spectrum bandwidth and production cost. These results show that the prism splitting is more suitable for the space-borne high resolution hyper spectral imager.