高光谱分辨率宽刈幅温室气体探测光谱仪设计

Design of High Spectral Resolution and Wide Swath Spectrometer for Greenhouse Gas Detection

为了探测地球大气中的温室气体含量,设计了4种空间分辨率为2 km、地面刈幅宽度为500 km、轨道高度为690 km的气体探测仪光学系统。4个波段的中心波长分别为1.606μm(弱CO_2)、1.660μm(CH_4)、2.064μm(强CO_2)和0.765μm(O_2);光谱分辨率分别为0.08nm/20000、0.08 nm/20000、0.1032 nm/20000和0.045 nm/17000。整个光学系统由浸没式平面衍射光栅、利特罗式光学结构以及前置系统构成。该系统在奈奎斯特频率处的调制传递函数(Modulation Transfer Function,MTF)值接近80%,且单个像元尺寸内集中了接近90%的衍射能量,可以实现高光谱探测。

To detect the concentration of greenhouse gas in the atmosphere of the earth, four kinds of gas detection optical systems with the spatial resolution of 2 kin, the ground swath of 500 km and the orbit altitude of 690 km are designed. The central wavelengths of the four wavebands are 1.606 μm （weak CO2）, 1.660 μm （CH4）, 2.064 μm （strong CO2） and 0.765 μm （02） respectively. Their spectral resolutions are 0.08 nm/20000, 0.08 nm/20000, 0.1032 nm/20000 and 0.045 nm/17000 respectively. The whole system consists of an immersed plane diffraction grating, a Littrow optical structure and a front optical system. Its Modulation Transfer Function （MTF） at the Nyquist frequency is close to 80% and the diffraction energy in a single pixel size is close to 90%. So, the system can be used to implement hyper spectral detection.