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P: Plasmaphysik
P 15: Diagnostik 2; Niedertemperaturplasmen / Plasmatechnologie 5; Plasma-Wand Wechselwirkung 1
P 15.6: Poster
Dienstag, 28. März 2006, 17:00–19:00, Flure
Pulsed Quantum Cascade Lasers as a Light Source for Cavity Ring-Down Spectroscopy — •St. Welzel1, G. Lombardi2, R. Engeln3, F. Hempel1, S. Glitsch1, D. C. Schram3, P. B. Davies4, and J. Röpcke1 — 1INP Greifswald, Friedrich-Ludwig-Jahn-Str. 19, 17489 Greifswald, Germany — 2CNRS LIMHP, Université Paris XIII, 99, av. J.B. Clément, 93430 Villetaneuse, France — 3Department of Applied Physics, Eindhoven University of Technology, P.O. Box 51, 5600 MB Eindhoven, The Netherlands — 4University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB21EW, Great Britain
Since more than 10 years cavity ring-down spectroscopy (CRDS) has been applied as a highly sensitive absorption technique in the visible spectral range. Short laser pulses which are injected into a cavity, formed by highly reflecting mirrors, allow for absorption lengths of hundreds of metres. However, due to a lack of suitable light sources this measurement concept has been hardly used in the mid infrared spectral range (MIR). Particularly, this No-dqfingerprint rangeNo-dq is of special interest for the investigation of stable and unstable molecules in reactive plasmas.
In the last years a new light source in the MIR became available: pulsed quantum cascade lasers (QCLs). Operating at room temperature, QCLs also exhibit a higher output power compared to other semiconductor based lasers in the MIR. A custom made compact quantum cascade laser measurement and control system (Q-MACS) combined with a pulsed QCL and ZnSe mirrors (R = 99.7 %) were used for CRDS in the MIR. The first measurements demonstrated the potential of this approach to become an extremely sensitive absorption technique in the MIR.