Regensburg 2007 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: POSTER: INTERNAL SYMPOSIUM Optical Spectrosopy

CPP 22.16: Poster

Mittwoch, 28. März 2007, 16:00–18:30, Poster B

Monitoring of Single-Chromophor Lifetime Fluctuations by Single-Photon Autocorrelation — Ruben Schmidt¹, •Thomas Blaudeck¹, Achim Gruber^1,2, and Frank Cichos^1,2 — ¹Photonics and Optical Materials, TU Chemnitz, 09107 Chemnitz, Germany — ²Molecular Nanophotonics, 04103 Leipzig, Germany

We report on a technique of time-resolved single-photon counting to monitor the fluctuations in the fluorescence lifetime of single chromophors. When analyzing the single-photon data in terms of a lifetime-intensity correlation, fluctuations can be assigned to either the radiative or the non-radiative decay rate of the excited state. In particular, the case of highly non-exponential fluorescence decays observed for semiconductor nanocrystals is discussed. Here, single-photon autocorrelation allows to assign a change of the fluorescence lifetime on the timescale of several microseconds. This reveals the emissive state to be rather a distribution of states than a single one.