基于菲涅耳透镜和法布里-珀罗干涉仪的飞秒激光光丝NaCl气溶胶荧光光谱探测  

Spectra Detection of NaCl Aerosol Fluorescence Induced by Femtosecond Laser Filament Based on Fresnel Lens and Fabry-Perot Interferometer

作　　者：金康 赵星[1,2] 张楠 刘伟伟[1,2] Jin Kang;Zhao Xing;Zhang Nan;Liu Weiwei(Institute of Modern Optics,College of Electronic Information and Optical Engineering,Nankai University,Tianjin 300350,China;Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology,Tianjin 300350,China)

机构地区：[1]南开大学电子信息与光学工程学院现代光学研究所,天津300350 [2]天津市微尺度光学信息技术科学重点实验室,天津300350

出　　处：《中国激光》2023年第7期83-92,共10页Chinese Journal of Lasers

基　　金：国家重点研发计划(2018YFB0504400);开放项目(BEP21C003)。

摘　　要：设计并制备了口径为20 mm的法布里-珀罗干涉仪,该干涉仪在632.8 nm处的光谱分辨率为0.5 nm,自由光谱范围为9.0 nm。将口径为1.1 m的低成本菲涅耳透镜用作集光元件,使用自行搭建的法布里-珀罗干涉仪和工业电荷耦合器件(CCD)相机成功探测到30 m外平均功率为0.7 mW的汞灯光谱,实现了μlx量级的弱光光谱探测。采用增强型互补金属氧化物半导体(ICMOS)相机,可在10 m外检测到飞秒激光光丝诱导的质量分数为13×10^(-6)的NaCl气溶胶的时间分辨荧光光谱。建立的基于菲涅耳透镜和法布里-珀罗干涉仪的光谱测量装置在空气污染物和有害物质远程检测中具有广阔的应用前景。Objective Aerosol is the general term for solid,liquid,and other particulate material in the atmosphere.The possible sources of aerosol include the combustion of biological substances and fossil fuels,mineral dust,and other harmful pollutant particles.When the concentration of NaCl aerosol in the atmosphere is higher than a threshold concentration,it inhibits plant growth,corrodes metals,harms the respiratory,cardiovascular,and cerebrovascular systems of human beings.When a femtosecond laser is transmitted in the air,owing to the nonlinear self-focusing effect,the focused light intensity reaches10~(13) W/cm~2.At this intensity,any substance in air is ionized and the fluorescence spectrum corresponding to the chemical composition of the substance is released.The composition and concentration of atmospheric pollutants can be detected based on this property by collecting and analyzing the fluorescence spectrum excited by the femtosecond laser filament,realizing air pollution monitoring and providing basic data for the formulation of air pollution control programs.Compared with the grating spectrometer,the light intensity collected by the Fabry-Perot interferometer (FPI) is 2-3 orders of magnitude larger than that of the grating spectrometer with the same spectral resolution.Simultaneously,because the aperture of the FPI is large,the spectrum of the extended light source can be measured directly,thus reducing the requirement of light-collecting elements.Based on the above characteristics,FPI is an ideal device for remote weak-light spectrum measurement.A Fresnel lens is considerably lighter and less expensive than the traditional spherical lens,which is suitable for the large-aperture low-light collection system.In this study,a Fresnel lens with an aperture of 1.1 m is used to converge remote low-light sources.Although the size of the focusing spot is large,it still can form a remote low-light spectrum detection system with the large-aperture FPI.Methods The Fresnel lens used in this study is made of polymethyl metha

关 键 词：光谱学 法布里-珀罗干涉仪 菲涅耳透镜 远程光谱探测 光丝诱导荧光光谱 

分 类 号：O433.1[机械工程—光学工程] TN203[理学—光学]