J. Phys. IV France 125 (2005) 597-599
Trace gas detection of C2H4 by photoacoustic spectroscopy using a compact pulsed optical parametric oscillatorT.-L. Wee1, J. Ng1, A.H. Kung1, A. Miklós2 and P. Hess2
1 Institute of Atomic Molecular Sciences, Academia Sinica, Taipei 106, Taiwan R.O.C., PO Box 23-166, Taipei, Taiwan
2 Institute of Physical Chemistry, University of Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
A compact pulsed optical parametric oscillator operated in an optical cavity with a grazing-incidence grating configuration was used to demonstrate sensitive photoacoustic detection of trace quantities of ethylene (C2H4). An IR wavelength within the absorption band of ethylene that produces minimal signal interference by background gases was identified. Using this IR wavelength, a concentration sensitivity of 10 parts in 109 by volume of C2H4 in nitrogen was measured with 60 mW of IR power in a single-pass configuration. The method of measuring the signal by fixing the IR wavelength at the absorption peak was compared with that of scanning the IR wavelength across the absorption maximum.
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