基于石英增强光声光谱技术的大气NO_(2)探测研究  

Detection of Atmosphere NO_(2)Based on Quartz Enhanced Photoacoustic Spectroscopy Technique

作　　者：王繁季 凌六一[1,2] 张浩鹏 高硕 WANG Fanji;LING Liuyi;ZHANG Haopeng;GAO Shuo(School of Electrical and Information Engineering,Anhui University of Science and Technology,Huainan 232001,China;School of Artificial Intelligence,Anhui University of Science and Technology,Huainan 232001,China)

机构地区：[1]安徽理工大学电气与信息工程学院,淮南232001 [2]安徽理工大学人工智能学院,淮南232001

出　　处：《光子学报》2024年第12期183-193,共11页Acta Photonica Sinica

基　　金：国家自然科学基金项目(No.41305139);安徽省重点研究与开发计划(No.202004i07020011);安徽理工大学研究生创新基金(No.2023cx2085)。

摘　　要：设计了一种用于大气NO_(2)检测的共轴石英增强光声光谱系统,该石英音叉采用T字头结构,利用有限元分析软件对音叉进行仿真,得到其前6阶模态振型和共振频率,并与音叉频率标定实验进行对比,标准大气压下其共振频率为12464.5 Hz,品质因数为12850。其中传感器气室体积仅为7 cm^(3),具有体积小、质量轻的优点。使用150 mW的半导体激光器,在405 nm波长处发射激光,实验优化了气体流速对噪声的影响,对NO_(2)浓度和光声信号值进行拟合,R^(2)为0.999,在1 s平均时间和标准大气压下,NO_(2)的探测灵敏度为3.09×10^(-9),对应的归一化噪声等效吸收系数为1.32×10^(-8)cm^(-1)·W·Hz^(-1/2),延长平均时间为434 s时,最低探测极限为3.2×10^(-8)。对大气NO_(2)连续两周实时监测,其与环境监测站的数据吻合度基本一致,验证了该传感器的稳定性和可靠性。The Quartz-enhanced Photoacoustic Spectroscopy(QEPAS)technology boasts high sensitivity,rapid response,and compact size.It has emerged as one of the prominent methods for detecting atmospheric pollutants in recent years.The on-beam Quartz Tuning Fork(QTF),with its superior anti-interference capability and stronger photoacoustic coupling effect compared to off-beam quartz tuning forks,serves as the foundation for designing a on-beam quartz-enhanced photoacoustic spectroscopy system for atmospheric NO_(2)detection.The quartz tuning fork,adopting a T-shaped structure,reduces resonance frequency while maintaining a high quality factor,thus increasing the amplitude of the photoacoustic signal.Finite element analysis using COMSOL Multiphysics software simulates the tuning fork,revealing its first six modal shapes and resonance frequencies.The fourth vibration mode is identified as symmetrical and effective,with a simulated characteristic frequency of 12418 Hz.Experimental calibration of the tuning fork's resonance frequency under standard atmospheric pressure yields 12464.5 Hz with a quality factor of 12850,indicating a relative error of 0.37%compared to the simulation model,affirming the model's validity.The acoustic detection module of the NO_(2)sensor features a chamber volume of only 7 cm^(3),offering the advantages of small size and light weight.The laser source for the NO_(2)quartz-enhanced photoacoustic spectroscopy sensor employs a 150 mW Xilong Optoelectronics DL_405 semiconductor laser emitting at a wavelength of 403.56 nm with a full width at half maximum of 0.84 nm.The NO_(2)absorption cross-section in the central wavelength spectral region is approximately 5.9485×10^(-19)cm^(2)/molecule.The coupled power after optical coupling,measured using a Hamamatsu S1223-01 photodiode,is 45.6 mW.Experimentation optimizes the impact of gas flow rate on noise,with noise levels rapidly increasing above 80 sccm,thus selecting 60 sccm as the optimal flow rate.Evaluation of the NO_(2)quartz-enhanced photoacoustic spectrosc

关 键 词：光声光谱 石英音叉 有限元仿真 NO_(2) 气体传感 

分 类 号：TN247[电子电信—物理电子学]