Regensburg 2019 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 3: Molecular Electronics and Excited State Properties
CPP 3.4: Vortrag
Montag, 1. April 2019, 10:30–10:45, H13
Ultrafast excited state relaxation monitored by single molecule photon statistics — •Jakob Schedlbauer1, Philipp Wilhelm1, Maria-Elisabeth Federl1, Florian Hinderer2, Sigurd Höger2, Lennart Grabenhorst3, Phillip Tinnefeld3, Jan Vogelsang3, Sebastian Bange1, and John M. Lupton1 — 1Universität Regensburg, Germany — 2Universität Bonn, Germany — 3LMU München, Germany
A new experimental approach is presented to monitor ultrafast excited state deactivation combining single molecule fluorescence spectroscopy (SMS) with a pump-probe-like excitation scheme. In the simplest way a single molecule can be described as a two level system and therefore can emit only one single photon after a given excitation pulse, a phenomenon referred to as photon antibunching. By introducing a second excitation pulse after a variable time lag the probability for reexciting the system and generating a second photon is a function of the excited state lifetime. A Hanbury-Brown-Twiss based detection setup enables us to measure the probability for the emission of multiple photons after a given excitation cycle.
This technique overcomes the limitation of conventional fluorescence based lifetime measurements such as time-correlated single-photon counting, which is constrained by finite detector instrument response function. We resolve dynamical single molecule processes like the intramolecular energy transfer in a acceptor-donor-acceptor system (13 ps) as well as ultrafast enhanced PL of Cy7 dyes coupled to a plasmonic antenna structure (20 ps).