We report the first application of a thermoelectrically cooled, distributed-feedback quantum-cascade laser for continuous spectroscopic monitoring of CO in ambient air at a wavelength of 4.6 µm. A noise-equivalent detection limit of 12 parts per billion was demonstrated experimentally with a 102-cm optical pathlength and a 2.5-min data acquisition time at a 10-kHz pulsed-laser repetition rate. This sensitivity corresponds to a standard error in fractional absorbance of 3 × 10-5.
© 2002 Optical Society of America
Original Manuscript: October 5, 2001
Published: February 20, 2002
Anatoliy A. Kosterev, Frank K. Tittel, Rüdeger Köhler, Claire Gmachl, Federico Capasso, Deborah L. Sivco, Alfred Y. Cho, Shawn Wehe, and Mark G. Allen, "Thermoelectrically cooled quantum-cascade-laser-based sensor for the continuous monitoring of ambient atmospheric carbon monoxide," Appl. Opt. 41, 1169-1173 (2002)