ABSTRACT
Numerical and experimental study of the mode tuning technique effects. Application to the cavity ring-down spectroscopy
Jerome Remy, Gerrit Kroesen, Winfred Stoffels, Eindhoven University of Technology Applied physics dept, den Dolech 2 PO Box 513, 5600 MB Eindhoven, The Netherlands – EU
Cavity Ring-Down Spectroscopy (CRDS) has historically primarily made use of pulsed lasers as light sources. Our experiment however is based on 0.1 mW CW multimode lead-salt laser diodes emitting in the mid-infrared wavelength range. In order to interrupt the laser beam and reach similar effects to pulsed light sources, a novel technique called “mode tuning” has been chosen, based on a small detuning of the incoming laser wavelength. This work exhibits the numerical predictions of that method, depending mainly on the field reflectivity of the Fabry-Perot cavity mirrors and the piezoelectric transducer speed. Emphasis will be brought on the oscillations that occur in the case of our ringing cavity, leading to a theoretical value of the cavity finesse. This work also provides experimental results that help us validate our simulation and point out the detection range limits of our CRDS set-up.
This work is supported by the European Union as part of the H-Alpha project under contract NNE5-1999-004 and by the Dutch Centrum voor Plasmafysica en Stralingstechnologie
