Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 72: Symposium: Beyond Optical Wavelengths: Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation II (Invited Speakers: Wilfried Wurth, Hermann Dürr, Shik Shin)

O 72.1: Hauptvortrag (ohne Erstattung)

Donnerstag, 28. Februar 2008, 14:00–14:30, HE 101

First Experiments at FLASH and the Core-Hole Clock — •Wilfried Wurth — Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149

Time-resolved soft x-ray spectroscopy has the potential to provide unique element specific and chemical state selective information on the complex wave packet evolution at surfaces and interfaces.

With the core-hole-clock method this potential has been utilized to determine ultrafast electron delocalization at specific atomic sites. However, here, dynamic information is only accessible in the time range given by the fixed decay time of core-excited states. In order to really follow the temporal evolution at selected atomic sites, we have to develop atom specific and chemically selective X-ray spectroscopy further towards a femtosecond time resolving technique.

With the Free-Electron Laser in Hamburg (FLASH) at DESY a unique source for femtosecond XUV-pulses with unprecedented brillance is operational since 2005. In the talk I will present some ideas how femtosecond X-ray pulses from Free Electron Lasers can be used to study surface and interface dynamics. First time-resolved experiments from FLASH will be presented and implications for future experiments will be discussed.

This work is supported by the BMBF in the framework of the Forschungschwerpunkt 301 FLASH: Matter in the light of ultrafast and extremely intense X-ray pulses.