Reconstruction and fitting of second-harmonic signals by wavelength modulation spectroscopy method based on fast Fourier transform

Linquan Lai, Yue Chen, Kongtao Chen, Jiale Tang, Kaiwen Yin, Fuqiang Jia, Dun Qiao, Yuanlong Fan, Kang Li, Nigel Copner

Allbwn ymchwil: Cyfraniad at gyfnodolynErthygladolygiad gan gymheiriaid

Crynodeb

Conventional wavelength modulation spectroscopy (WMS) is vulnerable to the influence of low-frequency noise. Accuracy of the method highly depends on the performance of the costly lock-in amplifier. In this article, we report a new and effective method for reconstructing second-harmonic signals through WMS based on fast Fourier transform (FFT). This method is less disturbed by low-frequency noise because it does not use a low-frequency ramp wave. Formulation and detection procedures were presented. The discrete second-harmonic waveform can be obtained by continuously changing the DC signal and FFT analysis in this method. Second-harmonic waveforms acquired by the two means are generally consistent. The experimental study validates the obtained gas concentration from 5% to 30%, showing a good linear relationship by the proposed method. The maximum relative error on concentration extraction is 2.87%; as for conventional WMS, this value is 4.50%. The developed measurement method may have potential in computed tomography.
Iaith wreiddiolSaesneg
Rhif yr erthygl093001
Nifer y tudalennau5
CyfnodolynChinese Optics Letters
Cyfrol20
Rhif cyhoeddi9
Dynodwyr Gwrthrych Digidol (DOIs)
StatwsCyhoeddwyd - 15 Meh 2022

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