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O: Fachverband Oberflächenphysik

O 87: Symposium: Beyond Optical Wavelengths: Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation III (Invited Speakers: Christian Spielmann, Matias Bargheer, Philippe Wernet)

O 87.2: Invited Talk (no funding)

Friday, February 29, 2008, 10:00–10:30, HE 101

Direct observation of lattice dynamics by femtosecond x-ray diffraction — •Matias Bargheer — Institut für Physik, Uni Potsdam, Am Neuen Palais 10, 14469 Potsdam — Max-Born-Institut, Max-Born-Str. 2a, 14489 Berlin

The ultrafast photoinduced lattice dynamics of hybrid nanolayers composed of oxides with perovskite crystal structure is investigated by femtosecond x-ray diffraction, using a laser-based table-top hard-x-ray plasma source. The coupling of the optically excited electrons in metallic layers to optical phonon modes and the directed phonon-phonon coupling to particular modes is unravelled by directly observing the lattice motion in real time with sub-picosecond time resolution and sub-picometer accuracy of the structural information. In particular, the photoassisted ultrafast manipulation of ferroelectric polarization by switching giant strain in the GPa range is demonstrated.