基于柔性空芯光纤的NO与NO2中红外吸收光谱检测(特邀)
Mid-Infrared Absorption Spectroscopy for NO and NO2 Detection in a Flexible Hollow Core Fiber(Invited)
温大新 1高丽梅 2段锟 1吉雍彬 1石艺尉 2任伟1
作者信息
- 1. 香港中文大学机械与自动化工程学系,香港 999077
- 2. 复旦大学信息科学与工程学院,上海 200433
- 折叠
摘要
报道了一种基于柔性空芯光纤和量子级联激光器(QCL)的中红外吸收光谱技术,可同时检测NO和NO2气体.QCL在间歇连续波(iCW)模式下运行,结合柔性空芯光纤具有小型化传感器的潜力.分别选择1929.03 cm-1和1599.91 cm-1的吸收线用于NO和NO2检测,两束激光同时耦合到内径为530 μm的100 cm长的柔性空芯光纤中.直接吸收光谱首先用于展示双气体检测,QCL以iCW模式运行并结合时分复用技术,然后采用一次谐波归一化的波长调制光谱来消除非气体吸收带来的信号强度变化的影响,并研究了气体传感器的性能.对于体积分数为50×10-6的NO与15×10-6的NO2,检测精度分别评估为5.2%和4.1%.当积分时间为60 s时NO的检测限为39×10-9,当积分时间为50 s时NO2的检测限为9.2×10-9.
Abstract
In this study,we report the application of mid-infrared absorption spectroscopy for simultaneous gas sensing of NO and NO2 using a flexible hollow core fiber(HCF)and two quantum cascade lasers(QCLs).The utilization of QCLs with intermittent continuous wave(iCW)operations and a flexible hollow-core optical fiber can miniaturize sensor systems.The optimal absorption lines for NO and NO2 detection were selected at approximately 1929.03 cm-1 and 1599.91 cm-1,respectively.Both laser beams were simultaneously coupled into a 100 cm flexible HCF with an inner diameter of 530 μm.Initially,direct absorption spectroscopy was performed as an intuitive demonstration of the iCW operation of QCLs with a time-division multiplexing(TDM)strategy for dual-species detection.Following this,we applied wavelength modulation spectroscopy using the first harmonic normalized second harmonic(2f/1f)method to eliminate the influence of any nonabsorption intensity variation,thereby enabling us to thoroughly investigate the performance of the gas sensor.The precision of NO and NO2 detection was estimated by measuring the concentrations of 50×10-6 NO and 15×10-6 NO2.Results indicated a precision of 5.2%for NO and 4.1%for NO2.Furthermore,we achieved minimum detection limits of 39×10-9 NO with a 60 s integration time and 9.2×10-9 NO2 with a 50 s integration time.
关键词
激光吸收光谱/柔性空芯光纤/间歇连续波/一氧化氮/二氧化氮Key words
laser absorption spectroscopy/flexible hollow core fiber/intermittent continuous wave/nitric oxide/nitrogen dioxide引用本文复制引用
基金项目
国家自然科学基金(52122003)
香港研资局优配研究项目(14208221)
香港研资局协作研究项目(C4002-22Y)
出版年
2024
NETL
NSTL
万方数据