Spectroscopy and Spectral Analysis, Volume. 32, Issue 3, 586(2012)
Multi-Harmonic Analysis of Quasi-Continuous-Wave Laser Modulation Absorption Spectroscopy
Numerous harmonic components such as multiple frequency, sum frequency and difference frequency of multiple modulation signals were found in quasi-continuous-wave (QCW) diode laser modulation absorption spectroscopy. Then, the authors analyzed these harmonic components’ existence in terms of non-linear interactions of laser and gas absorption line. And the signals’ characteristics were studied experimentally. The results shows that there are some sum frequency and difference frequency components that have larger amplitudes compared to the second harmonic wavelength modulation spectroscopy signal (2f-WMS) commonly used in tunable diode laser spectroscopy (TDLAS), and it may improve the detection sensitivity of QCW modulation spectroscopy.
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QI Ru-bin, DU Zhen-hui, MENG Fan-li, LI Jin-yi, GAO Dong-yu, XU Xiao-bin, CHEN Wen-liang, XU Ke-xin. Multi-Harmonic Analysis of Quasi-Continuous-Wave Laser Modulation Absorption Spectroscopy[J]. Spectroscopy and Spectral Analysis, 2012, 32(3): 586
Received: Jun. 29, 2011
Accepted: --
Published Online: Apr. 16, 2012
The Author Email: Ru-bin QI (qirubin@gmail.com)