Diode laser spectroscopy provides exceptional sensitivity and selectivity for real-time characterization of reacting systems and gas streams. High frequency wavelength modulation techniques achieve species detection limits that are routinely in the ppm range and can reach sub-ppb levels under favorable conditions. Narrow laser linewidths guarantee selective detection of key species even in the presence of myriad other components. Diode laser spectroscopy is also relatively immune from interference by black body radiation or chemiluminescence. Prototype diode-laser based systems have been demonstrated successfully for trace gas detection in turbulent, high temperature particle-laden streams, for oxygen quantitation in flames, for free radical characterization in a plasma etching reactor and for greenhouse gas flux measurements in air. We also discuss the availability of laser wavelengths, compatibility with fiber optics, cost safety and expectations for new laser development.

Date Published: 14 August 1992
PDF: 11 pages
Proc. SPIE 1681, Optically Based Methods for Process Analysis, (14 August 1992); doi: 10.1117/12.137730

Published in SPIE Proceedings Vol. 1681:
Optically Based Methods for Process Analysis
David S. Bomse; Harry Brittain; Stuart Farquharson; Jeremy M. Lerner; Alan J. Rein; Cary Sohl; Terry R. Todd; Lois Weyer, Editor(s)