Using quantum cascade lasers with resonant optical cavities as a diagnostic tool

S. Welzel, G. Lombardi, P.B. Davies, R.A.H. Engeln, D.C. Schram, J. Röpcke

Onderzoeksoutput: Hoofdstuk in Boek/Rapport/CongresprocedureConferentiebijdrageAcademicpeer review

Samenvatting

Absorption spectroscopy based on optical resonators is known to be a very sensitive diagnostic technique. For many years the infrared spectral range could not be employed, because of the lack of suitable radiation sources with the required power and tunability. Recent advances in semiconductor laser technology, in particular the advent of quantum cascade lasers (QCL) provides new possibilities for highly sensitive and selective detection of molecular species. Cavity Enhanced Absorption Spectroscopy (CEAS) with a thermoelectrically (TE) cooled cw QCL emitting at 7.66 µm and employing a ~0.5 m long cavity yielded effective path lengths of 1080 m and a sensitivity of 2 x 10-7 cm-1 Hz-1/2, mainly limited by incomplete averaging over cavity resonances. The molecular concentration detection limit with a 20 s integration time was found to be 6 x 108 molecules/cm3 for N2O and 2 x 10 9 molecules/cm3 for CH4 which is good enough for the selective measurement of trace atmospheric constituents at 2.2 mbar. © 2009 IOP Publishing Ltd
Originele taal-2Engels
TitelProceedings of the 3rd International Workshop on Infrared Plasma Spectroscopy, 23–25 July 2008, Greifswald, Germany
RedacteurenP.B. Davies, J. Röpcke, F. Hempel
Plaats van productieBristol
UitgeverijInstitute of Physics
Pagina's012009-1/8
DOI's
StatusGepubliceerd - 2009

Publicatie series

NaamJournal of Physics: Conference Series
Volume157
ISSN van geprinte versie1742-6588

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