基于二次谐波峰高-峰宽特征的免标定波长调制光谱方法  

Calibration-Free Wavelength Modulation Spectroscopy Method Based on the Height-Width Characteristic of Second Harmonic

作　　者：王一红 周宾 赵荣 汪步斌 Wang Yihong;Zhou Bin;Zhao Rong;Wang Bubin(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,School of Energy and Environment,Southeast University,Nanjing 210096,Jiangsu,China)

机构地区：[1]东南大学能源与环境学院能源热转换及其过程测控教育部重点实验室,江苏南京210096

出　　处：《光学学报》2022年第20期209-217,共9页Acta Optica Sinica

基　　金：国家重点研发计划(2017YFB0603204);国家自然科学基金(50976024,50906013)。

摘　　要：提出一种基于二次谐波峰高-峰宽特征的免标定波长调制光谱方法,并给出任意调制系数下,考虑Voigt线型的光谱吸收率二次谐波峰高-峰宽解析表达式。与传统的谐波波形拟合方法相比,所提方法只需要进行一次滤波处理,对计算资源要求更低;不需要利用HITRAN 2020数据库中的碰撞加宽系数、温度依赖指数等光谱参数,理论上更加适用于复杂气体组分下的测量。在实验室搭建WMS测量系统开展室温下CH_(4)摩尔分数的测量实验,实验结果表明,在20 cm光程下,当CH_(4)摩尔分数大于2.08×10^(-3)时,所提方法的测量相对偏差小于2%。This paper proposes a calibration-free wavelength modulation spectroscopy(WMS)method based on the heightwidth characteristic of the second harmonic and gives the analytical expression of the height and width of the second harmonic for the spectral adsorption factor considering the Voigt line-shape function under arbitrary modulation index.Compared with the traditional harmonic waveform fitting method,this method only requires filtering processing once and has lower requirements for computing resources.Instead of using spectral parameters such as collisional broadening coefficients and temperature-dependent indexes from the HITRAN 2020 database,it is theoretically more suitable for measurements under complex gas components.A WMS measurement system is set up in the laboratory to measure the mole fraction of CH_(4)at room temperature.The experimental results reveal that when the mole fraction of CH_(4)is greater than 2.08×10^(-3) under the 20 cm optical path,the relative deviation of the proposed method is less than 2%.

关 键 词：光谱学 吸收光谱 波长调制 免标定 快速算法 甲烷检测 

分 类 号：TN219[电子电信—物理电子学]