An innovative spectroscopic technique based on balancing and cancellation of modulated signals induced by two excitation sources. We used quartz enhanced photoacoustic spectroscopy (QEPAS) in a 2f wavelength modulation mode as an absorption sensing technique and employed a modulation cancelation approach for spectroscopic measurements of small temperature differences in a gas mixture and detection of broadband absorbers. We demonstrated measurement of small temperature differences in a C2H2/N(2)gas mixture with a sensitivity of 30 mK in 17 sec and detection of hydrazine, a broadband absorbing chemical species, down to concentration of 1 part per million in volume in 1 sec. In both cases we used near-infrared laser diodes and selected overtone transitions
Modulation cancellation method (MOCAM) in modulation spectroscopy / Spagnolo, V.; Dong, L.; Kosterev, A. A.; Thomazy, D.; Doty, J. H.; Tittel, F. K.. - STAMPA. - 8073:(2011). (Intervento presentato al convegno Conference on Optical Sensors and Photonic Crystal Fibers V tenutosi a Prague, Czech Republic nel April 18-20, 2011) [10.1117/12.886272].
Modulation cancellation method (MOCAM) in modulation spectroscopy
V. Spagnolo;
2011-01-01
Abstract
An innovative spectroscopic technique based on balancing and cancellation of modulated signals induced by two excitation sources. We used quartz enhanced photoacoustic spectroscopy (QEPAS) in a 2f wavelength modulation mode as an absorption sensing technique and employed a modulation cancelation approach for spectroscopic measurements of small temperature differences in a gas mixture and detection of broadband absorbers. We demonstrated measurement of small temperature differences in a C2H2/N(2)gas mixture with a sensitivity of 30 mK in 17 sec and detection of hydrazine, a broadband absorbing chemical species, down to concentration of 1 part per million in volume in 1 sec. In both cases we used near-infrared laser diodes and selected overtone transitionsI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
