Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 82: Electronic Structure of Surfaces 2
O 82.5: Talk
Friday, September 9, 2022, 11:30–11:45, S053
Single-Molecule Ultrafast Fluorescence-Detected Pump--Probe Microscopy — •Daniel Fersch1, Pavel Malý1,2, Jessica Rühe3, Victor Lisinetskii1, Matthias Hensen1, Frank Würthner3,4, and Tobias Brixner1,4 — 1Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic — 3Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 4Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg, Germany
The spectroscopic signatures of bulk samples can differ vastly from those of the respective single molecules. In particular, access to the femtosecond dynamics of single molecules remains a large experimental challenge. Here, we present a novel setup consisting of a spectrally tunable femtosecond laser source and a scanning confocal fluorescence microscope with fully reflective excitation geometry and single-molecule sensitivity. Using a phase-stable interferometer we create a pulse pair with variable time delay to measure the molecular fluorescence excitation spectrum by means of Fourier-transform spectroscopy. By exciting the molecule with an additional prior pump pulse, we gain access to the dynamics of the excited state as a function of the pump--probe delay, resulting in a fluorescence-detected pump--probe spectrum. We have obtained first results on single terrylene bisimide molecules and compare them to a spincoated thin film.