基于QEPAS技术的痕量气体高灵敏度检测系统研究  

Study on high sensitive trace gas detection based on QEPAS

作　　者：林成[1] 张雪莲 严学阳 蔡燕[1] LIN Cheng;ZHANG Xuelian;YAN Xueyang;CAI Yan(College of Physics and Electronic Information Engineering,Neijiang Normal University,Neijiang Sichuan 641100,China)

机构地区：[1]内江师范学院物理与电子信息工程学院,四川内江641100

出　　处：《激光杂志》2024年第9期40-46,共7页Laser Journal

基　　金：四川省自然科学基金(No.2022NSFSC0525);内江师范学院科研项目(No.2021ZD11)。

摘　　要：搭建了一种用于乙炔痕量气体高灵敏度探测的全光式石英音叉增强型光声光谱系统。为了提高系统探测灵敏度,采用光功率放大技术提高激励光源功率,采用直角棱镜使激光束穿过两个共振管,采用光纤珐珀传感技术测量音叉叉股面外单向振动代替面内对称振动;同时利用自稳定技术提高系统的稳定性。采用有限元分析方法对传统商用石英音叉的振动进行了模拟和分析。在对激光调制深度、微共振管结构尺寸和激光输出功率等参数优化基础上,得到了2.9 ppb的系统检测极限,归一化等效噪声系数为2.4×10^(-9)cm^(-1)·W·Hz^(-1/2);二次谐波信号幅值与C_(2)H_(2)浓度呈现良好的线性关系,其线性相关系数达到0.999。最后经过1小时的连续实验验证了通过自稳定技术可以有效提高系统的稳定性。An all-optical quartz-enhanced photoacoustic spectroscopy(QEPAS)system for the highly sensitive detection of acetylene trace gas was proposed.An erbium-doped fiber amplifier(EDFA),a right-angle prism and a fiber Fabry-Perot interferometer(FPI)for out-of-plane one-way vibration detection were employed to improve the detection sensitivity.A self-stabilization technology was used to further improve the stability of the system.The vibration of commercial quartz tuning forks was simulated by the finite element analysis.Parameters such as laser modulation coefficient,structural size of the acoustic microresonator and output power of laser were optimized.A C_(2)H_(2)minimum detectable limit(MDL)of 2.9 ppb was achieved,with a corresponding normalized noise equivalent absorption coefficient of 2.4×10^(-9)cm^(-1)·W·Hz^(-1/2).The 2f signal amplitude shows a good correlation with the C2H2 concentration,with a linear correlation coefficient of 0.999.Finally,a 1-hour continuous experiment verified that the self-stabilization technology can effectively improve the stability of the system.

关 键 词：石英增强光声光谱 全光式 光纤珐珀传感 功率放大 面外单向振动 

分 类 号：TN209[电子电信—物理电子学]