宽光谱棱镜型太阳光谱仪设计

Design of Prism Spectrometer with Wide Spectral Coverage for Solar Spectrum Measurement

为实现大气层外太阳光谱辐照度(SSI)变化的长期例行监测,设计了一种星载宽光谱太阳光谱仪结构。全系统仅使用单片折反式曲面棱镜实现太阳光谱250～2500nm的分光,并通过棱镜转动实现谱平面上多探测器的同步扫描探测;同时基于Huygens子波点扩展函数(PSF)仿真了光谱仪的光谱响应函数(SRF)和光谱分辨率。分光棱镜在±2.5°扫描转角内的全谱段子午像差小于8μm;光谱分辨率在紫外谱段(250～400nm)为0.7～3.5nm,可见/近红外谱段(400～1000nm)为3.5～35.0nm,短波红外谱段(1000～2500nm)内为28.5～41.2nm。整个系统结构简单紧凑,性能稳定可靠,分光和像差校正能力满足大气层外太阳光谱辐照度长期监测需求。

A satellite-borne solar spectrometer with wide spectral coverage is designed to routinely monitor the long- term variability of solar spectral irradiance （SSI） outside the atmosphere. The instrument employs only one prism with curved surfaces for the dispersion of solar spectrum from 250 nm to 2500 nm, which are scanned simultaneously by several detectors on the focal plane as the prism rotates. The spectral response function （SRF） and spectral resolution of the instrument are also simulated based on Huygens wavelet point spread function （PSF）. The tangential aberration of all the wavelengths is smaller than 8 t^m at each prism rotation angle within ±2.5°. The wavelength resolution is 0.7 - 3.5 nm in ultraviolet region （250 - 400 nm）, 3.5 - 35.0 nm in visual/near-infrared （400-1000 nm） and 28. 5-41.2 nm in short-wave infrared （1000-2500 nm）. The structure of the system is simple and compact, and the performance is stable and reliable. The spectral dispersion and aberration correction capacity satisfy demand of the long-term measurement of SSI at the top of atmosphere.