Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 26: Photobiophysics

BP 26.7: Talk

Friday, March 27, 2009, 12:30–12:45, ZEU 260

Resolution limits in nanobiophotonics — •Franz-Josef Schmitt — Institut für Optik und Atomare Physik, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin

According to recent progress in high resolved fluorescence microscopy literature presents new relations for the spatial resolution limit suggesting a principally infinite resolution of fluorescing pigments. We show that similar relations would also be found for the time resolution and present examples where time- and space-correlated single photon (TSCSPC) counting is used to determine sub-nm distances and sub-ps energy transfer and exciton relaxation processes in biophysical pigment-protein complexes (e.g. plant proteins containing chlorophyll). Up today TSCSPC still did not reach an unbreakable limitation of the resolution. We show results of 24 h measurements which are limited by the long time stability of the sample and the long time stability of the measurement setup. The possible refinements of these both stability problems are shortly discussed (e.g. by correction of thermal drift, deep temperature measurements to reduce photobleaching). Even in a principal approach without respect to sample and setup stability one will find that an infinite resolution is not possible although fluorescence spectroscopy might be still far away from the principal lower bound of resolution for arbitrary big and arbitrary stable systems.