Osnabrück 2002 – wissenschaftliches Programm

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Q: Quantenoptik

Q 433: Poster: Laser – Grundlagen und Anwendungen

Q 433.22: Poster

Donnerstag, 7. März 2002, 16:30–18:30, Schloss

Determination of Photo-physical Parameters of Single Fluorescent Molecules via the Intensity Correlation Function — •Dirk Seidel and Gerhard C. Hegerfeldt — Institut für Theoretische Physik, Bunsenstr. 9, 37073 Göttingen, Germany

The observation of the fluorescence of single quantum systems has become possible 20 years ago for trapped ions and has also recently been achieved for single molecules in solids at low temperature. A molecule can show bright and dark periods in its fluorescence due to metastable triplet states, just as for single ions. The single-molecule spectroscopy has gained importance for the investigation of many effects in physical chemistry and biophysics and therefore the knowledge of molecular photo-physical parameters is essential.

We show by the example of terrylene in a crystalline host that it is possible to determine photo-physical parameters, like Einstein coefficients and the mean bright and dark periods, from the intensity correlation function (ICF). To do this we use our recently proposed approach for a simplified calculation of the ICF. It turns out that this approach is simpler and allows greater accuracy than other methods. In addition we obtain further parameters like the frequency of the various intensity periods or the probability density of photons scattered off the host crystal.