双光程光声光谱甲烷传感器  

Photoacoustic Spectroscopy Based Methane Sensor Using a Double-Pass Photoacoustic Cell

作　　者：杨艳芳[1,2] 裴凯龙 尹旭坤 武红鹏 李尚志[1,2] 崔茹悦 马维光[1,2] 张雷 尹王保 董磊[1,2] 贾锁堂 

机构地区：[1]量子光学与光量子器件国家重点实验室山西大学激光光谱研究所,山西太原030006 [2]极端光学协同创新中心,山西太原030006

出　　处：《光谱学与光谱分析》2018年第2期616-620,共5页Spectroscopy and Spectral Analysis

基　　金：国家优秀青年基金项目(61622503);国家自然科学基金项目(61575113)资助

摘　　要：利用甲烷(CH_4)气体分子在1.6μm的吸收特性,使用中心波数为6 046.96cm^(-1)的蝶形分布反馈式(DFB)激光器和自制的大内径光声池,设计了一款紧凑高灵敏的CH_4气体传感器。为了进一步增强输出光声信号强度,一个具有高反射率的平面镜放置在光声池后,使透射光束被反射后,二次通过光声池,增强了光与被测气体的作用距离,使光声信号提高了1.9倍。传感器各项参数,包括调制频率、调制深度及气体流速被优化。在标准大气压和1s的积分时间下,该传感器最终获得的探测灵敏度为0.21ppm,1σ归一化等效噪声系数(NNEA)为2.1×10^(-8 )cm^(-1)·W·Hz^(-1/2)。该甲烷传感器使用性价比高的DFB近红外激光二极管作为激发光源,装置简单,成本低廉可以满足大气环境检测、矿井瓦斯监测、工业过程控制及无创伤医疗诊断等领域的需求。A laser based Photoacoustic sensor system was demonstrated and developed for methane（CH_4）detection using a custom double-pass photoacoustic cell with a large inner diameter.The sensor used a butterfly-package distributed feedback（DFB）laser with its wavelength targeting the CH_（4 ）absorption line at 6 046.96cm^（-1）.A high-reflection plane mirror was positioned behind the photoacoustic cell to enhance the absorption optical path and improve the detection sensitivity.The sensor parameters including the modulation frequency,modulation depth of the laser and gas flow were optimized.Under theatmospheric pressure,the novel CH_4sensor showed a detection sensitivity of 0.21ppm with a 1saveraging time,which corresponded to a1σnormalized noise equivalent absorption（NNEA）of 2.1×10^（-8 ）cm^（-1）·W·Hz^（-1/2）.The excellent performance of this CH_4sensor promises broad applicability to industry,mine,medical and environmental monitoring,etc.

关 键 词：甲烷检测 光声光谱 分布反馈式激光器 气体传感器 波长调制 

分 类 号：O433.1[机械工程—光学工程]