We report what we believe are the first spectroscopic measurements to be made with a room-temperature quantum-cascade distributed-feedback laser. Using wavelength modulation spectroscopy, we detected N2O and CH4 in the chemical fingerprint wavelength range near 8µm . The noise equivalent absorbance for our measurement was 5 parts in 105, limited by excess amplitude modulation on the laser output, which corresponds to a 1-Hz bandwidth detection limit of 250 parts N2O in 109 parts N2 in a 1-m path length.
© 1998 Optical Society of America
(140.5960) Lasers and laser optics : Semiconductor lasers
(280.3420) Remote sensing and sensors : Laser sensors
(300.1030) Spectroscopy : Absorption
(300.6340) Spectroscopy : Spectroscopy, infrared
K. Namjou, S. Cai, E. A. Whittaker, J. Faist, C. Gmachl, F. Capasso, D. L. Sivco, and A. Y. Cho, "Sensitive absorption spectroscopy with a room-temperature distributed-feedback quantum-cascade laser," Opt. Lett. 23, 219-221 (1998)