Berlin 2008 – scientific programme
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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 72.3: Talk
Thursday, February 28, 2008, 14:45–15:00, HE 101
Single-shot femtosecond EUV-pump/visible-probe cross-correlation on GaAs — •Theophilos Maltezopoulos1, Stefan Cunovic2, Marek Wieland3, Martin Beye3, Armin Azima1, Harald Redlin1, Maria Krikunova3, Roland Kalms3, Ulrike Fruehling1, Filip Budzyn3, Wilfried Wurth3, Alexander Foehlisch3, and Markus Drescher3 — 1HASYLAB at DESY, Notkestrasse 85, 22607 Hamburg, Germany — 2Department of Physics, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld, Germany — 3Institut fuer Experimentalphysik, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
The Free Electron Laser in Hamburg (FLASH) is currently the most intense femtosecond light source in the extreme-ultraviolet (EUV) range, which facilitates efficient pumping of inner shells in solid targets. For pump-probe experiments, a synchronized optical fs laser system is available at the facility. In our set-up, the EUV pulse (wavelength 28 nm, pulse length 20-30 fs) and the visible pulse (400 nm, 130 fs) are non-collinearly overlapped in space and time on the surface of a GaAs crystal. Along its path, the EUV pump pulse changes the reflectivity of the GaAs sample for the visible probe pulse, the latter being imaged onto a CCD array. The spatial position of the reflectivity change captures the dynamics of the process in a single exposure. The technique can be utilized to determine individual EUV-visible delays with a precision of about 40 fs.