Berlin 2014 – wissenschaftliches Programm
Q 30: Poster: Photonics, laser development and applications, ultrashort laser pulses, quantum effects
Q 30.48: Poster
Dienstag, 18. März 2014, 16:30–18:30, Spree-Palais
Investigation of Fluorescence Suppression in a Capillary Raman System — •Hendrik Seitz1, Simone Rupp1, Magnus Schlösser1, Beate Bornschein1, and Helmut H. Telle2 — 1Institute for Technical Physics, Tritium Laboratory Karlsruhe, Karlsruhe Institute of Technology, Germany — 2Department of Physics, Swansea University, United Kingdom
Raman spectroscopy is a widely used tool for analyzing the composition of gas mixtures. It allows non-contact and inline multispecies gas measurements. A highly sensitive Raman system for detecting small amounts of gases can be realized by using a glass capillary with a silvered inner surface as the gas cell. The laser light is sent through the capillary which offers a long scattering region, while the highly reflective silvering makes it possible to collect a large fraction of the Raman-scattered light. Both the long scattering region and the effective Raman light collection lead to a high signal. A disadvantage of this approach, however, is the high fluorescence background. Fluorescence light is produced by laser light in glass, in this special case if the laser hits the capillary frontally or if laser light tunnels through the silvering into the glass. This poster discusses a new approach to suppress this fluorescence light for gaining even higher sensitivities: the glass capillary is replaced by a metal tube made of highly reflective metals, e.g. gold, silver or aluminium. An overview of the challenges connected to this approach is given, and the results of first comparison measurements between the metal tubes and the glass capillary are presented.