Laser & Optoelectronics Progress, Volume. 59, Issue 13, 1330003(2022)
Research on Tunable Diode Laser Absorption Spectroscopy Background Signal Drift Correction
In this study, a gas volume fraction-inversion method is proposed to solve the drifting issue of the second harmonic background signal in the wavelength modulation spectroscopy technology. Here, the signal similar to the measured second harmonic signal in the background signal history data is taken as the background signal. First, a laser with a central wavelength of ~5.18 μm is used to build a NO volume fraction measurement system and a background signal library is constructed using the pure N2 background signal measured within 48 h as historical data. Subsequently, the NO is passed into the system, and the absorbed second harmonic signal and the correlation coefficient between it and each background signal in the background signal library is calculated. Finally, the volume fraction of the gas is retrieved after subtracting the background signal from the maximum correlation coefficient. The NO with a volume fraction of 2.5 × 10-6 is monitored for 24 h, and the results show that the method could decrease the average relative error from 6.48% before correction to 3.84%.
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Min Zhang, Jian Fang, Yong Wang, Wenxiong Mo, Fangzhou Hao, Fan Yang, Xiang Lin. Research on Tunable Diode Laser Absorption Spectroscopy Background Signal Drift Correction[J]. Laser & Optoelectronics Progress, 2022, 59(13): 1330003
Category: Spectroscopy
Received: Jul. 8, 2021
Accepted: Aug. 17, 2021
Published Online: Jul. 1, 2022
The Author Email: Zhang Min (ZhangM_scut@126.com)