title: Photoacoustic spectroscopy using quantum-cascade lasers.
abstract: Photoacoustic spectra of ammonia and water vapor were recorded by use of a continuous-wave quantum-cascade distributed-feedback (QC-DFB) laser at 8.5 mum with a 16-mW power output. The gases were flowed through a cell that was resonant at 1.6 kHz, and the QC-DFB source was temperature tuned over 35 nm for generation of spectra or was temperature stabilized on an absorption feature peak to permit real-time concentration measurements. A detection limit of 100 parts in 10(9) by volume ammonia at standard temperature and pressure was obtained for a 1-Hz bandwidth in a measurement time of 10 min.
authors: B A
authors: BA
authors: Paldus
authors: T G
authors: TG
authors: Spence
authors: R N
authors: RN
authors: Zare
authors: J
authors: J
authors: Oomens
authors: F J
authors: FJ
authors: Harren
authors: D H
authors: DH
authors: Parker
authors: C
authors: C
authors: Gmachl
authors: F
authors: F
authors: Cappasso
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