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O: Fachverband Oberflächenphysik

O 43: Poster Session II - MA 141/144 (Surface Spectroscopy on Kondo Systems; Frontiers of Surface Sensitive Electron Microscopy; Methods: Scanning Probe Techniques+Electronic Structure Theory+Other; Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation; joined by SYNF posters)

O 43.43: Poster

Dienstag, 26. Februar 2008, 18:30–19:30, Poster F

A femtosecond X-ray/optical cross-correlator: Free-electron laser X-ray pulse induced transient optical reflectivity — •Cornelius Gahl1,4, Armin Azima3, Martin Beye2, Martin Deppe2, Kristian Döbrich1, Urs Hasslinger2, Franz Hennies2,5, Alexej Melnikov1, Mitsuru Nagasono2, Annette Pietzsch2, Martin Wolf1, Wilfried Wurth2, and Alexander Föhlisch21Fachbereich Physik, Freie Universität Berlin — 2Institut für Experimentalphysik, Universität Hamburg — 3HASYLAB/DESY, Hamburg — 4Max-Born-Institut Berlin — 5MAX-lab, Lund Universitet, Sweden

Due to their short pulse duration and high brilliance over a wide range of photon energies free-electron-laser (FEL) based femtosecond x-ray pulse sources make possible completely new classes of experiments. Since it is extremely difficult to precisely synchronize a FEL with an external femtosecond laser source, one has to measure the relative arrival time of x-ray and optical pulse to perform pump-probe experiments with optimal time resolution. At the Free-Electron-Laser in Hamburg (FLASH) we exploited the high peak brilliance for this purpose by measuring the x-ray induced transient change in optical reflectivity at a GaAs surface. The ultrafast drop in reflectivity on the time scale of the pulse duration enables us to determine the temporal overlap of x-ray and optical pulses as well as the statistical timing jitter and a systematical drift within a pulse train. Therefore this easy to implement technique denotes an important step towards delay control for femtosecond time-resolved experiments and opens up the field of femtosecond X-ray induced dynamics.

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DPG-Physik > DPG-Verhandlungen > 2008 > Berlin