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HL: Fachverband Halbleiterphysik

HL 3: 2D Materials I – Excitonic properties

HL 3.10: Vortrag

Montag, 9. März 2026, 12:00–12:15, POT/0081

Coherent two-dimensional electronic spectroscopy integrated with confocal microscopy for probing 2D materials — •Trideep Kawde, Pavel Trofimov, Matteo Russo, Anton Trenczek, and Hélène Seiler — Freie Universität Berlin, 14195, Berlin, Germany

Two-dimensional electronic spectroscopy is a powerful tool for probing ultrafast processes in van der Waals materials and heterostructures. As these structures are typically only 10x100 µ m in size and highly heterogeneous, the challenge of ultrafast studies on such materials is to balance requirements in spatial and angular resolutions - often requiring highly dispersive microscope objectives - with temporal resolution. We present a coherent 2D electronic spectroscopy setup integrated with a confocal back focal plane imaging setup, featuring high magnification, spatial and angle resolution, while maintaining a time resolution of ∼15 femtosecond. We demonstrate this approach on an exfoliated WSe₂ monolayer. The data reveal <100 femtosecond homogeneous linewidth broadening of the A exciton lineshape, indicating rapid exciton-energy fluctuations. These measurements provide insight into dephasing mechanisms such as excitation-induced dephasing, which sets fundamental limits to coherent control and quantum-optical applications.

Keywords: 2D materials; two-dimensional electronic spectroscopy; Ultrafast technique; Excitons; monolayer WSe2