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Optical Engineering • Open Access

High-sensitivity detection of trace gases using dynamic photoacoustic spectroscopy
Author(s): Charles M. Wynn; Stephen T. Palmacci; Michelle L. Clark; Roderick R. Kunz

Paper Abstract

Lincoln Laboratory of Massachusetts Institute of Technology has developed a technique known as dynamic photoacoustic spectroscopy (DPAS) that could enable remote detection of trace gases via a field-portable laser-based system. A fielded DPAS system has the potential to enable rapid, early warning of airborne chemical threats. DPAS is a new form of photoacoustic spectroscopy that relies on a laser beam swept at the speed of sound to amplify an otherwise weak photoacoustic signal. We experimentally determine the sensitivity of this technique using trace quantities of SF 6 gas. A clutter-limited sensitivity of ∼100  ppt is estimated for an integration path of 0.43 m. Additionally, detection at ranges over 5 m using two different detection modalities is demonstrated: a parabolic microphone and a laser vibrometer. Its utility in detecting ammonia emanating from solid samples in an ambient environment is also demonstrated.

Paper Details

Date Published: 28 August 2013
PDF: 6 pages
Opt. Eng. 53(2) 021103 doi: 10.1117/1.OE.53.2.021103
Published in: Optical Engineering Volume 53, Issue 2
Show Author Affiliations
Charles M. Wynn, MIT Lincoln Lab. (United States)
Stephen T. Palmacci, MIT Lincoln Lab. (United States)
Michelle L. Clark, MIT Lincoln Lab. (United States)
Roderick R. Kunz, MIT Lincoln Lab. (United States)

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