title: Trace-gas detection in ambient air with a thermoelectrically cooled, pulsed quantum-cascade distributed feedback laser.
abstract: A pulsed quantum-cascade distributed feedback laser operating at near room temperature was used for sensitive high-resolution IR absorption spectroscopy of ambient air at a wavelength of approximately 8 microm. Near-transform-limited laser pulses were obtained owing to short (approximately 5-ns) current pulse excitation and optimized electrical coupling. Fast and slow computer-controlled frequency scanning techniques were implemented and characterized. Fast computer-controlled laser wavelength switching was used to acquire second-derivative absorption spectra. The minimum detectable absorption was found to be 3 x 10(-4) with 10(5) laser pulses (20-kHz repetition rate), and 1.7 x 10(-4) for 5 x 10(5) pulses, based on the standard deviation of the linear regression analysis.
authors: Rice Quantum Institute, Rice University, Houston, Texas 77251-1892, USA. akoster@rice.edu
authors: A A
authors: AA
authors: Kosterev
authors: F K
authors: FK
authors: Tittel
authors: C
authors: C
authors: Gmachl
authors: F
authors: F
authors: Capasso
authors: D L
authors: DL
authors: Sivco
authors: J N
authors: JN
authors: Baillargeon
authors: A L
authors: AL
authors: Hutchinson
authors: A Y
authors: AY
authors: Cho