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Proceedings Paper

Real time ammonia detection in exhaled human breath using a distributed feedback quantum cascade laser based sensor
Author(s): Rafał Lewicki; Anatoliy A. Kosterev; David M. Thomazy; Terence H. Risby; Steven Solga; Timothy B. Schwartz; Frank K. Tittel
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Paper Abstract

A continuous wave, thermoelectrically cooled, distributed feedback quantum cascade laser (DFB-QCL) based sensor platform for the quantitative detection of ammonia (NH3) concentrations present in exhaled human breath is reported. The NH3 concentration measurements are performed with a 2f wavelength modulation quartz enhanced photoacoustic spectroscopy (QEPAS) technique, which is very well suited for real time breath analysis, due to the fast gas exchange inside a compact QEPAS gas cell. An air-cooled DFB-QCL was designed to target the interference-free NH3 absorption line located at 967.35 cm-1 (λ~10.34 μm). The laser is operated at 17.5 °C, emitting ~ 24 mW of optical power at the selected wavelength. A 1σ minimum detectable concentration of ammonia for the line-locked NH3 sensor is ~ 6 ppb with 1 sec time resolution. The NH3 sensor, packaged in a 12"x14"x10" housing, is currently installed at a medical breath research center in Bethlehem, PA and tested as an instrument for non-invasive verification of liver and kidney disorders based on human breath samples.

Paper Details

Date Published: 24 January 2011
PDF: 7 pages
Proc. SPIE 7945, Quantum Sensing and Nanophotonic Devices VIII, 79450K (24 January 2011); doi: 10.1117/12.874887
Show Author Affiliations
Rafał Lewicki, Rice Univ. (United States)
Anatoliy A. Kosterev, Rice Univ. (United States)
David M. Thomazy, Rice Univ. (United States)
Terence H. Risby, The Johns Hopkins Univ. (United States)
Steven Solga, St. Luke's Hospital (United States)
Timothy B. Schwartz, St. Luke's Hospital (United States)
Frank K. Tittel, Rice Univ. (United States)

Published in SPIE Proceedings Vol. 7945:
Quantum Sensing and Nanophotonic Devices VIII
Manijeh Razeghi; Rengarajan Sudharsanan; Gail J. Brown, Editor(s)

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