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Proceedings Paper

Tunable diode laser spectroscopy with wavelength modulation: first harmonic integration method for acetylene absorption line profile recovery
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Paper Abstract

A novel method for recovering gas absorption line profile basing on tunable diode laser spectroscopy (TDLS) and wavelength modulation (WM) is presented. WM combines residual amplitude modulation (RAM) and distorts harmonic components since the phase lag between amplitude modulation (AM) and frequency modulation (FM)/ wavelength modulation (WM). Fourier decomposition of Lorentzian profile assumed for absorption line profile in the case of wavelength modulation is described in order to discuss the distortion of harmonic components by RAM. Pure first harmonic is separated from RAM distortion and integrated for recovering the actual absorption line profile in the case of low modulation index. Photoacoustic spectroscopy (PAS) is applied since the high efficiency for gas sensing in different fields, especially using the acoustic resonator as gas cell in order to enhance the photoacoustic signal and obtain high sensitivity. A good agreement between experimental result and theoretical simulation for line profile recovery of acetylene P17 absorption line at 1535.39nm is achieved.

Paper Details

Date Published:
Proc. SPIE 7598, Optical Components and Materials VII, 75981Z; doi: 10.1117/12.842804
Show Author Affiliations
Li Li, Jilin Univ. (China)
Univ. of Strathclyde (United Kingdom)
Yiding Wang, Jilin Univ. (China)
George Stewart, Univ. of Strathclyde (United Kingdom)
Graham Thursby, Univ. of Strathclyde (United Kingdom)
Norhana Arsad, Univ. of Strathclyde (United Kingdom)
Brian Culshaw, Univ. of Strathclyde (United Kingdom)

Published in SPIE Proceedings Vol. 7598:
Optical Components and Materials VII
Shibin Jiang; Michel J. F. Digonnet; John W. Glesener; J. Christopher Dries, Editor(s)

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