SKM 2023 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 33: Poster II

HL 33.60: Poster

Wednesday, March 29, 2023, 17:00–19:00, P1

Time-gated coherent two-dimensional spectroscopy on the nanoscale — •Luisa Brenneis, Julian Lüttig, Matthias Hensen, and Tobias Brixner — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg

The observation of the temporal dynamics of excitons, i.e., electron-hole pairs, is essential for the understanding of fundamental phenomena in nature, e.g., photosynthesis [1]. The method of optical two-dimensional (2D) spectroscopy has proven to be particularly suitable for this purpose. For example, electronic couplings and energy transport phenomena can be directly revealed as cross peaks in a 2D spectrum, i.e., a correlation spectrum of excitation and probe frequency as a function of time. To additionally decipher the spatial dynamics of a system in a nanostructured environment beyond the optical diffraction limit, we have combined 2D spectroscopy with photoemission electron microscopy to realize coherent “2D nanoscopy” [2,3]. Here, using coupled molecular dimers in numerical simulations, we investigate the potential of 2D nanoscopy. In particular, we show how the exciton and biexciton dynamics can be disentangled by resolving the kinetic energy spectrum of photoemitted electrons and by realizing a time gate using an additional ionization pulse.

[1] T. Brixner et al., Nature 434, 625-628 (2005).

[2] M. Aeschlimann et al., Science 333, 1724 (2011).

[3] S. Pres et al., Nat. Phys. (2022) (accepted).