Photoacoustic spectroscopy using quantum-cascade lasers.
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.
Paldus
B A
BA
Spence
T G
TG
Zare
R N
RN
Oomens
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J
Harren
F J
FJ
Parker
D H
DH
Gmachl
C
C
Cappasso
F
F
Sivco
D L
DL
Baillargeon
J N
JN
Hutchinson
A L
AL
Cho
A Y
AY