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MO: Molekülphysik
MO 14: Spektroscopy II
MO 14.4: Talk
Friday, April 6, 2001, 16:30–16:45, H1058
High sensitive multicomponent photoacoustic trace-gas sensing based on CO2 - and quantum-cascade lasers as light sources — •Markus Nägele1, D. Lauchenauer1, M.W. Sigrist1, R. Hollmann2, E. Kammer2, D. Hofstetter3, T. Aellen3, M. Beck3, and J. Faist3 — 1Swiss Federal Institute of Technology (ETH), Institute of Quantum Electronics, CH-8093 Zürich, Switzerland, e-mail: sigrist@iqe.phys.ethz.ch — 2Kantonsspital Aarau, Klinik für Plastische- und Wiederherstellungschirurgie, CH-5001 Aarau, Switzerland — 3University of Neuchâtel, Institute of Physics, CH-2000 Neuchâtel, Switzerland
We present a novel mobile photoacoustic laser spectrometer using line-tunable cw 12CO2 -, 13CO2 -, and pulsed Peltier-cooled quantum-cascade lasers (QCLs) as pump sources. The emission wavelengths of both laser types are in the 10 µm region with an output power of 1-10 W for the CO2 lasers and up to 250 mW peak power for the QCLs. The minimum measurable absorption coefficient is 10−9 cm−1 (CO2 laser) and 10−5 cm−1 (QCLs) for a signal-to-noise ratio of 3.
The performance of the system is illustrated by trace gas measurements in different environments, e.g. by an analysis of fume generated from electroknife surgery on human tissue. These fumes contain dozens of species at low concentrations, some of them presumably toxic or even cancerogenic.