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Proceedings Paper

Spectroscopic benzene detection using a broadband monolithic DFB-QCL array
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Paper Abstract

Quantitative laser spectroscopic measurements of complex molecules that have a broad absorption spectra require broadly tunable laser sources operating preferably in the mid-infrared molecular fingerprint region. In this paper a novel broadband mid-infrared laser source comprising of an array of single-mode distributed feedback quantum cascade lasers was used to target a broadband absorption feature of benzene (C6H6), a toxic and carcinogenic atmospheric pollutant. The DFB-QCL array is a monolithic semiconductor device with no opto-mechanical components, which eliminates issues with mechanical vibrations. The DFB-QCLs array used in this work provides spectral coverage from 1022.5 cm-1 to 1053.3 cm-1, which is sufficient to access the absorption feature of benzene at 1038 cm-1 (9.64 μm). A sensor prototype based on a 76 m multipass cell (AMAC-76LW, Aerodyne Research) and a dispersive DFB-QCL array beam combiner was developed and tested. The Allan deviation analysis of the retrieved benzene concentration data yields a short-term precision of 100 ppbv/Hz1/2 and a minimum detectable concentration of 12 ppbv for 200 s averaging time. The system was also tested by sampling atmospheric air as well as vapors of different chemical products that contained traces of benzene.

Paper Details

Date Published: 10 March 2016
PDF: 7 pages
Proc. SPIE 9767, Novel In-Plane Semiconductor Lasers XV, 97671T (10 March 2016); doi: 10.1117/12.2213696
Show Author Affiliations
Rafał Lewicki, Princeton Univ. (United States)
Mark Witinski, Pendar Technologies (United States)
Harvard Univ. (United States)
Biao Li, Pendar Technologies (United States)
Gerard Wysocki, Princeton Univ. (United States)


Published in SPIE Proceedings Vol. 9767:
Novel In-Plane Semiconductor Lasers XV
Alexey A. Belyanin; Peter M. Smowton, Editor(s)

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