Berlin 2001 – wissenschaftliches Programm

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MO: Molekülphysik

MO 14: Spektroscopy II

MO 14.4: Vortrag

Freitag, 6. April 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.