被动差分吸收光谱技术(DOAS)是一种以太阳散射光为光源,利用不同气体分子的特征吸收来实现气体 定性定量测量的方法。成像光谱技术作为一种新型光电探测技术,能同时获取观测区域的空间信息 和光谱信息,该技术与DOAS结合构成了成像差分吸收光谱系统(IDOAS),可实现对气体的二维成像测 量。设计了基于凸面光栅Offner成像光谱仪、面阵CCD、紫外镜头和扫描旋转台的成像差分吸收 光谱系统,描述了系统的组成并着重介绍了Offner成像光谱仪的光学设计。针对该系统开发了基 于MFC框架的软件系统,实现了探测器参数设置、数据采集与显示、数据存储、电机扫描控制、 多波段成像、图谱合一等功能。利用该系统对发电厂烟羽排放进行外场测量,采用被动差分吸 收光谱方法对采集的太阳散射光谱进行处理获得SO2 柱浓度,实验证明系统运行稳定可靠,可用 于污染气体的二维成像解析。

Based on finger print absorption, the technique of passive differential optical absorption spectroscopy (DOAS) enables the qualitative and quantitative measurement of a variety of pollutants found in the atmosphere using scattering light as light source. As a new type of photoelectric detection technology, imaging detection technology can get the spatial and spectral information of the detection area at the same time, which makes it possible to realize two-dimensional imaging measurement of the pollutants when combined with passive DOAS. The experimental system consisted of convex grating Offner imaging spectrometer, matrix CCD, UV lens and scan table is introduced, and the optical design of the Offner imaging spectrometer is described in detail. The software system based on MFC was developed, which realized such functions as: detector parameter setting, data acquisition and display, data storage, the control of scan table, imaging of the target, and the combination of image with spectrum. The system was carried to scan the plume from a fossil power plant in a field measurement. And the column density of SO2 was retrieved from processing of the scattered sun light spectra collected by the system by means of the spectral analysis method of passive DOAS. The results show that the system can run stably and be used to realize two-dimension imaging measurement of the pollutants.