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Q: Fachverband Quantenoptik und Photonik
Q 49: Laseranwendungen: Laserspektroskopie
Q 49.5: Talk
Thursday, March 17, 2011, 11:30–11:45, SCH A215
Off-beam QEPAS with divergent light sources — •Stefan Böttger1, Ulrike Willer1, Martin Angelmahr2, and Wolfgang Schade1,2 — 1Clausthal University of Technology, Energie-Forschungszentrum Niedersachsen, EnergieCampus, Am Stollen 19, 38640 Goslar — 2Fraunhofer Heinrich Hertz Institute, EnergieCampus, Am Stollen 19, 38640 Goslar
Photoacoustics is an established method of spectroscopy. Eight years ago the application of quartz tuning forks as resonant sensor elements found its way into the photoacoustic spectroscopy known as QEPAS (quartz-enhanced photoacoustic spectroscopy). The high Q-factor of the tuning fork leads to high achievable sensitivities combined with small sensor dimensions. Since the introduction of QEPAS various configurations and applications have been found. However, the submillimeter diameter of the acoustic resonator demanded for laser sources with excellent beam quality so far. In a new approach, the so-called off-beam resonator design, the tuning fork is no longer positioned in the beam path. Since the light only needs to penetrate the acoustic resonator its geometry can be adapted according to the light source. This enables to utilize low beam quality light sources like high-power laser diodes or LEDs. In this investigation we present the detection of ozone with off-beam QEPAS using different divergent light sources.