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Proceedings Paper

Photothermal beam deflection applied to SO2 trace detection
Author(s): Francisco Adriano Manzano; V. D'Accurso; O. Radulovich
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Paper Abstract

We present the application to environmental monitoring of a compact setup for in situ trace gas detection based on photothermal beam deflection (mirage effect) spectroscopy. Gas traces measurements are performed by detecting the time-varying component of the photothermal deflection of a red diode laser beam, propagating inside the region where a pollutant is excited by another laser. In this work, detection of traces of SO2 in a mixture with Nitrogen at atmospheric pressure enclosed in a glass cell, was performed using the fourth-harmonic pulses of a 10 Hz Nd:YAG laser. It was verified by FTIR spectroscopy that negligible SO2 destruction was produced after irradiation of high pressure mixtures with 105 UV pulses. Several beam sizes and propagating angles for the UV and visible laser were tested and evaluated in order to overcome parasitic signals due to unwanted absorption in optical elements. With this setup we reached a detection limit of 5 ppbV in a hundred-second averaging time span but we estimate sub-ppbV levels can be reached by simple changes in the geometry for improving the signal to noise ratio.

Paper Details

Date Published: 21 October 2004
PDF: 4 pages
Proc. SPIE 5622, 5th Iberoamerican Meeting on Optics and 8th Latin American Meeting on Optics, Lasers, and Their Applications, (21 October 2004); doi: 10.1117/12.590920
Show Author Affiliations
Francisco Adriano Manzano, CEILAP (CITEFA-CONICET) (Argentina)
V. D'Accurso, CEILAP (CITEFA-CONICET) (Argentina)
O. Radulovich, CONICET (Argentina)


Published in SPIE Proceedings Vol. 5622:
5th Iberoamerican Meeting on Optics and 8th Latin American Meeting on Optics, Lasers, and Their Applications

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