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Proceedings Paper

New dispersive method for measuring weak pollutant concentration
Author(s): Yuri S. Galkin; Victor N. Kharchenko
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Paper Abstract

It is known that the tunable diode laser spectroscopy provides a very high degree of selectivity and sensitivity of the detection of gaseous components. For the evaluation of the mean density of a specific molecular constituent, the differential absorption method is employed. Recently it was shown that probing by a frequency-modulated single sideband signal and measuring the resulting radio-frequency beat signal phase relates absorption and dispersion and provides a species detection limit well below 1 part per billion if a multiple-pass cell is used. More recently it was shown that the dispersive properties near to the absorption lines of a matter can be used for concentration measurements. Now the theoretical research is showing that the nonlinearity of the refractive index near an absorption and more workable than the beat phase. The short pulse laser promotes excellent temporal and spatial resolution of pollutant detecting and analysis. This idea may also be used for the laser remote sensing by short pulses.

Paper Details

Date Published: 18 January 1999
PDF: 7 pages
Proc. SPIE 3533, Air Monitoring and Detection of Chemical and Biological Agents, (18 January 1999); doi: 10.1117/12.336863
Show Author Affiliations
Yuri S. Galkin, Moscow State Forestry Univ. (Russia)
Victor N. Kharchenko, Moscow State Forestry Univ. (Russia)


Published in SPIE Proceedings Vol. 3533:
Air Monitoring and Detection of Chemical and Biological Agents
Joseph Leonelli; Mark L.G. Althouse, Editor(s)

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