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O: Fachverband Oberflächenphysik

O 70: Structural Dynamics in Nanoscale Materials Probed by Ultrashort Electron Pulses

O 70.15: Poster

Mittwoch, 18. März 2015, 18:15–21:00, Poster A

Inelastic scattering of low-energy electrons by optical near-fields — •Lars Drögemüller, Sascha Schäfer, and Claus Ropers — IV. Physical Institute, University of Göttingen, 37077 Göttingen, Germany

Ultrafast low-energy electron diffraction (ULEED) is a new tool in ultrafast surface science [1], which utilizes a laser-pump/electron-probe scheme to study the structural dynamics at surfaces and ultrathin films. For the future development of ULEED, a reliable and quantitative temporal characterization of the employed low-energy electron pulses is required. While inelastic near-field scattering was successfully applied for pulse characterization at high-energies [2, 3], its extension to the low-energy regime is challenging.

In this study, numerical simulations based on the finite-element-method were performed to investigate near-field electron scattering at low energies. Plasmonic effects and optical resonances in tailored nanostructures were considered to optimize the electron-photon scattering cross section.

[1] M. Gulde et al., Science 345, 200-4 (2014). [2] B. Barwick, D. J. Flannigan A. H. Zewail, Nature 462, 902-6 (2009). [3] F. O. Kirchner, A. Gliserin, F. Krausz, P. Baum, Nature Photonics 8, 52-57 (2013).