Regensburg 2025 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 7: Focus Session Ultrafast Electron Microscopy at the Space-Time Limit I
O 7.1: Vortrag
Montag, 17. März 2025, 10:30–10:45, H11
Ultrafast Low-Energy Electron Microscopy — •Johannes Otto1,2,3, Leon Brauns1,2, Benjamin Schröder1,2, and Claus Ropers1,2,3 — 1Department of Ultrafast Dynamics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany — 24th Physical Institute, University of Göttingen, Göttingen, Germany — 3Max Planck School of Photonics
Low-Energy Electron Microscopy (LEEM) allows for imaging the first atomic layers of a surface with nanometer resolution by reflecting a low-energy electron beam [1]. This contribution reports on the first implementation and initial results of Ultrafast LEEM. We replaced the electron source of a conventional instrument with a laser-triggered tip-shaped photoemitter enabling imaging with nanometer spatial and picosecond temporal resolution [2]. We show first real-space dynamics including a thermally-induced intensity suppression (transient Debye-Waller effect) and strain-wave propagation. Additionally, we report on stimulated inelastic electron-light scattering (IELS) at beam energies below 100 eV, as recently proposed theoretically [3]. The demonstrated capabilities of the instrument open up new possibilities to investigate a wide range of dynamical phenomena at surfaces.
[1] W. Telieps and E. Bauer, Surface Science 162, 163 (1985).
[2] A. Feist et al., Ultramicroscopy 176, 63 (2017).
[3] A. P. Synanidis et al., Sci. Adv. 10, eadp4096 (2024).
Keywords: iels; ultrafast; LEEM; Debye-Waller; uleem