The Study On Spectrum Test Technology With High Resolution Within O₂A Band

Global warming has been widespread concern around the world, thefundamental reason is the increasing emissions of greenhouse gases in theatmosphere, in which CO₂accounted for80percent of greenhouse gas emissions, isgenerally considered to be one of the most important factors of global warming.Therefore essential for the monitoring of the concentration of CO₂in the atmosphereis very necessary and is also the focal research of environmental protection aboutenergy-saving and emission-reduction in many countries. CO₂concentrationmeasurement is usually carried out by means of spectral analysis, in which O2Aband spectrum of atmospheric measurement accuracy will directly affect theprecision of the CO₂concentration inversion calculation. So the study of spectralcharacteristics of O₂A band is particularly important, in which O₂A bandhyperspectral test technology and test instrument is a prerequisite for the relevantresearch. This thesis is around the O₂A band high spectral resolution test system tocarry out the system design and related technologies research.This thesis first introduces the research background and practical significance,illustrates the necessity and urgency of the research work; then a more detaileddescription of the basic principles of the hyperspectral detection, especially appliedto atmospheric detection has made a more detailed introduction; next from theanalysis of influence of O₂A band spectrum on the CO₂concentration measurement,achieve the O₂A band spectral resolution affect the precision of the CO₂ concentration inversion calculation, further demonstrates the high spectral resolutiontest method of the O₂A band and put forward the system needed to achieve thetarget; in order to produce the holographic gratings that could satisfy therequirements of high spectral resolution test, one of a large-size, high-groove density,high wavefront quality holographic gratings exposure optical system was designed,by comparing the division-of-amplitude exposure optical system, in order to acquirehigh-quality diffraction wavefront, the exposure optical system with a large Abbenumber difference double separation lens group structure, at the same time by wayof compensation mirror alignment to achieve the test wavelength and the workwavelength have a common image plane, to facilitate the alignment processreal-time monitoring; followed by carried out the design of the test system with highspectral resolution within O₂A band, mainly to complete the optical design of thesystem, and the spectrum resolution can reach0.044nm, the design results has beencarried on the comprehensive evaluation of image quality and result analysis, andthe results meet the requirements of the high spectral test system target, the technicalindices of holographic grating was determined by optical design results, using thedeveloped exposure optical system to complete the development of the holographicgrating, at the same time developed a large-size holographic grating diffractionefficiency measurement tester and completed the grating diffraction efficiencymeasurement; the developed holographic gratings were applied to the O₂A bandhigh spectral resolution test system and spectral calibration, then completed thespectral calibration works and the relevant atmospheric observation experiments, theexperimental data show that the reasonable dispersive component selection,production to meet the requirements of the spectral resolution, while the indicatorsof the overall test system meet the requirements; at the end of the thesis on the workcarried out by the comprehensive summary and generalization, and the future workis prospected.In recent years, the CO₂concentration monitoring technology and methods inthe field of space applications has gradually become a hot scientific research around the world, but generally speaking, many key components and high spectralresolution technology are still in the exploratory stage. Therefore, the research workof this thesis is to promote the study of our country in the field of space CO₂concentration monitoring and related technologies, has the certain exploration andinnovation, and laid the foundation for the future research in various atmosphericcomposition measurements.