Aachen PK 2003 – scientific programme

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P: Plasmaphysik

P 10: Poster II

P 10.27: Poster

Tuesday, March 18, 2003, 17:30–19:15, Foyer

Fourier transform phase shift cavity ring down spectroscopy — •R. Zijlmans, A. Smets, E. Hamers, D. Schram, and R. Engeln — Department of Applied Physics (CPS), Eindhoven University of Technology, Eindhoven, the Netherlands

To perform sensitive, broadband absorption measurements at an intermediate resolution, a phase shift cavity ring down setup has been combined with a Fourier transform spectrometer. In this setup an incoherent continuous broadband light source is used to excite an optical cavity.

With this experimental setup it is possible to perform measurements in the wavelength range from 10 µm to 250 nm. The resolution is determined by the Fourier transform spectrometer, and the sensitivity can be increased by three orders of magnitude, compared to standard Fourier transform spectrometers.

The light from a modified cascaded arc, which is filled with Ar or Xe, is modulated at 100 kHz. When the light passes the optical cavity, it undergoes a wavelength dependent phase shift, which is analyzed by the Fourier transform spectrometer. The ratio of the Fourier transforms of the in-phase and out-of-phase components of the light leaking out of the cavity results in the cavity loss at every wavelength.