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Proceedings Paper

Gas phase photoacoustic spectroscopy in the long-wave IR using quartz tuning forks and amplitude modulated quantum cascade lasers
Author(s): Michael D. Wojcik; Mark C. Phillips; Bret D. Cannon
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Paper Abstract

We demonstrate the performance of a novel long-wave infrared photoacoustic laser absorbance spectrometer for gas-phase species using an amplitude modulated (AM) quantum cascade (QC) laser and a quartz tuning fork microphone. Photoacoustic signal was generated by focusing the output of a Fabry-Perot QC laser operating at 8.41 μm between the legs of a quartz tuning fork which served as a transducer for the transient acoustic pressure wave. The QC laser was modulated at the resonant frequency of the tuning fork (32.8 kHz). This sensor was calibrated using the infrared absorber Freon-134a by performing a simultaneous absorption measurement using a 35 cm absorption cell. The NEAS of this instrument was determined to be 2 x 10-8 W • cm / √Hz, and the fundamental sensitivity of this technique is limited by the noise floor of the tuning fork itself.

Paper Details

Date Published: 17 October 2006
PDF: 9 pages
Proc. SPIE 6386, Optical Methods in the Life Sciences, 63860S (17 October 2006); doi: 10.1117/12.685470
Show Author Affiliations
Michael D. Wojcik, Pacific Northwest National Lab. (United States)
Mark C. Phillips, Pacific Northwest National Lab. (United States)
Bret D. Cannon, Pacific Northwest National Lab. (United States)

Published in SPIE Proceedings Vol. 6386:
Optical Methods in the Life Sciences
Alexey A. Belyanin; Mostafa Analoui; Rebekah Anna Drezek; Claire F. Gmachl, Editor(s)

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