Dresden 2026 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 46: Ultra-fast Phenomena II
HL 46.4: Talk
Thursday, March 12, 2026, 16:15–16:30, POT/0051
Investigating exciton dynamics and exciton–exciton interactions via optical two-dimensional photoelectron spectroscopy — •Luisa Brenneis1, Matthias Hensen1, Julian Lüttig2, and Tobias Brixner1 — 1Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany — 2Department of Physics, University of Ottawa, 150 Louis-Pasteur Pvt, Church St, Ontario K1N 6N5, Canada
Action-detected two-dimensional (2D) electronic spectroscopy has become a powerful technique to resolve exciton dynamics by measuring an incoherent signal proportional to the excited-state population generated by a multi-pulse sequence. However, processes that alter the excited-state population after the system’s interaction with the pulse sequence, such as exciton–exciton annihilation, can obscure coupling signatures and single-exciton dynamics [1]. In optical 2D photoelectron spectroscopy (2DPES), typically a four-pulse sequence excites the system, followed by a time-delayed ionization pulse [2]. Here, we show how to disentangle exciton dynamics and interactions by varying the ionization pulse time delay. Exemplary simulations of a weakly coupled dimer demonstrate that short ionization delays reveal coupling signatures and single-exciton energy transfer, whereas longer delays reveal exciton–exciton annihilation. This concept is particularly promising for nanoscale surface studies, where 2DPES combined with photoemission electron microscopy enables spatially resolved exciton mapping.
[1] M. Bruschi et al., Phys. Chem. Lett. 14, 30, 6872 (2023).
[2] D. Uhl et al., Optica 8, 10, 1316 (2021).
Keywords: Ultrafast spectroscopy; Photoelectron detection; Time gate