A diode laser sensor has been applied to monitor CO, CO2, and CH4 in combustion gases with absorption spectroscopy and fast extraction-sampling techniques. Survey spectra of the CO 3ν band (R branch) and the 2ν1 + 2ν20 + ν3 CO2 band (R branch) near 6350 cm−1 and H2O lines from the ν1 + 2ν2 and 2ν2 + ν3 bands in the spectral region from 6345 to 6660 cm−1 were recorded and compared with calculated spectra (from the HITRAN 96 database) to select optimum transitions for species detection. Species concentrations above a laminar, premixed, methane–air flame were determined from measured absorption in a fast-flow multipass absorption cell containing probe-sampled combustion gases; good agreement was found with calculated chemical equilibrium values.
© 1997 Optical Society of America
Original Manuscript: January 27, 1997
Revised Manuscript: June 10, 1997
Published: November 20, 1997
Radu M. Mihalcea, Douglas S. Baer, and Ronald K. Hanson, "Diode laser sensor for measurements of CO, CO2, and CH4 in combustion flows," Appl. Opt. 36, 8745-8752 (1997)