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Proceedings Paper

Assessment of a QCL laser approach for the simultaneous measurement of ambient ammonia and ozone
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Paper Abstract

In this paper, we compare the open-path FTIR to the differential optical absorption spectroscopy (DOAS) approach in the Mid-Infrared region for the continuous retrieval of trace gases. After consideration of FTIR capabilities and results, we explore the potential for a compact quantum cascade laser (QCL) based DOAS system to continuously monitor ambient concentration levels of Ozone and Ammonia. Based on absorption spectra obtained from the HITRAN2000 database and processed within the GENSPECT environment, we find the optimal window for simultaneous retrieval of Ozone and Ammonia to be between 1045 (cm-1) and 1047 (cm-1). We further show that for a QCL-based transmitter with 0.1cm-1 spectral resolution and 10mW power and using nitrogen cooled MCT detector (D* ~ 1010 W-1m Hz1/2) in the receiver, it is possible to detect total path ambient concentrations of ozone and ammonia to within 10% accuracy using suitable targets of opportunity such as an building. Details of the optimal frequency sweeping methodology, optical path length, shot averaging, and SNR considerations are considered for comparison of the QCL-based standoff DOAS performance to more conventional open-path FTIR sensors.

Paper Details

Date Published: 25 September 2007
PDF: 8 pages
Proc. SPIE 6760, Infrared, Mid-IR, and Terahertz Technologies for Health and the Environment II, 676005 (25 September 2007); doi: 10.1117/12.734401
Show Author Affiliations
Viviana Vladutescu, City College, CUNY (United States)
Graduate Ctr., CUNY (United States)
Barry Gross, City College, CUNY (United States)
Fred Moshary, City College, CUNY (United States)
Samir Ahmed, City College, CUNY (United States)

Published in SPIE Proceedings Vol. 6760:
Infrared, Mid-IR, and Terahertz Technologies for Health and the Environment II
Alexey A. Belyanin; Rebekah A. Drezek; Claire Gmachl, Editor(s)

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