EC-QCL中红外激光外差光谱遥测技术研究  

Research on Middle Infrared Laser Heterodyne Remote Sensing Technology Based on EC-QCL

作　　者：沈凤娇 谈图 卢军[1] 张胜 高晓明 陈卫东 SHEN Feng-jiao;TAN Tu;LU Jun;ZHANG Sheng;GAO Xiao-ming;CHEN Wei-dong(School of Advanced Manufacturing Engineering,Hefei University,Hefei 230601,China;Anhui Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Hefei 230031,China;Laboratoire de Physico-Chimie de l’Atmosphère,Universitédu Littoral C te d’Opale,Dunkerque,59140,France)

机构地区：[1]合肥学院先进制造工程学院,安徽合肥230601 [2]中国科学院合肥物质科学研究院安徽光学精密机械研究所,安徽合肥230031 [3]Laboratoire de Physico-Chimie de l’Atmosphère,Universitédu Littoral C te d’Opale,Dunkerque,59140,France

出　　处：《光谱学与光谱分析》2023年第6期1739-1745,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41805018);安徽省自然科学基金项目(2208085QF218);安徽高校协同创新项目(GXXT-2019-048);合肥学院人才科研基金项目(20RC02);安徽省高校自然科学研究项目(KJ2021A0979)资助。

摘　　要：具有高灵敏度、高光谱分辨率的中红外激光外差光谱气体探测,是以窄线宽激光器作为本地振荡器,通过放大入射的微弱吸收信号,实现大气痕量气体柱浓度和垂直浓度廓线的遥感探测技术。基于当前的激光外差辐射计,提出了一种新型的仪器结构。引入直接吸收光谱系统实现外差系统工作波长的选定和频率标定。采用紧凑型红外黑体源EMIRS200作为宽带辐射光源,替代太阳光,进行激光外差系统的验证分析。为激光外差辐射计的下一步系统集成提供了新方法。研制了中红外宽调谐激光外差辐射计概念验证系统,对系统基本参数进行了测试分析。该系统采用8μm外腔量子级联激光器(EC-QCL)作为本地振荡光源,红外黑体源EMIRS200作为辐射光源。通过对该系统基本参数的测试数据分析,获得了系统信噪比(~120)和外差转换效率(~0.006)参数。利用艾伦方差分析确定了EC-QCL的稳定时间至少达到了133 s,因此非常适合于激光外差光谱的采集。得到直接吸收光谱系统的1σ最小体积分数探测限为2.312×10^(-8),能够满足大气甲烷高灵敏检测需求,同时实现外差系统工作波长的选定和频率标定。最后利用已建立的激光外差辐射计概念验证系统获取了甲烷中红外8μm处高分辨激光外差吸收光谱,并与甲烷在8μm波段附近的直接吸收光谱进行了光谱比对。最后拟合了系统光谱分辨率参数,验证了该概念验证系统的高光谱分辨率,能满足较窄线宽条件下的高分辨率激光外差光谱的测量。实验结果表明,激光外差系统中引入直接吸收光谱系统可以实现外差系统工作波长的选定和频率标定。紧凑型红外黑体源EMIRS200可以用于激光外差辐射计的结构优化,实现激光外差系统的分析验证,为进一步应用于测量实际大气中多组分气体的光谱提供了实验基础并拓展激光外差辐射计在高精度遥感探测领域的The mid-infrared(MIR)laser heterodyne spectroscopy with high sensitivity and high spectral resolution is a remote sensing technique for detecting atmospheric trace gas’s column concentration and vertical concentration profile by using a narrow linewidth laser as a local oscillator(LO)and amplifying the weak absorption signal.This paper proposes a new instrument structure based on the current laser heterodyne radiometer(LHR).A direct absorption spectrum system was introduced in the laser heterodyne system to realize the selection of working wavelength and frequency calibration.A compact IR blackbody source EMIRS200 was used as the broadband radiation source to replace sunlight and verify and analyze the laser heterodyne system.It provides a new method for the next system integration of LHR.A MIR-wide tuning LHR proof-of-concept(PoC)system was developed,and the basic parameters of the system were tested and analyzed.The system used an 8μm external cavity quantum cascade laser(EC-QCL)as the LO and an IR blackbody source,EMIRS200,as the radiation source.After testing and analyzing the basic parameters of the system,the signal-to-noise ratio(SNR)(~120)and heterodyne conversion efficiency(~0.006)of the system were measured.The stability time of EC-QCL measured was at least 133s using Allan variance analysis,so it is very suitable for laser heterodyne spectrum acquisition.The limit of detection(LoD)of the 1σminimum volume fraction of the direct absorption spectrum system was 2.312×10^(-8),which can meet the requirements of highly sensitive detection of atmospheric CH 4 and realize the selection of working wavelength and frequency calibration of the heterodyne system.Finally,the high-resolution heterodyne absorption spectrum of CH 4 at 8μm was obtained by using the established LHR PoC system and compared with the direct absorption spectra of CH 4 at 8μm.Finally,the spectral resolution parameters of the system were fitted,and the high spectral resolution of the LHR PoC system was verified,which can satisfy the high

关 键 词：大气遥感 外腔量子级联激光器 中红外 激光外差 

分 类 号：O433.5[机械工程—光学工程]