Berlin 2001 – wissenschaftliches Programm
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K: Kurzzeitphysik
K I: HV I
K I.1: Hauptvortrag
Montag, 2. April 2001, 15:30–16:15, EB107
Ultrafast time-resolved X-ray diffraction with Multi-keV femtosecond laser-plasma X-ray sources — •K. Sokolowski-Tinten1, C. Blome1, C. Dietrich1, A. Tarasevitch1, M. Horn von Hoegen1, D. von der Linde1, A. Cavalleri2, C.W. Siders2, J. Squier2, C.P.G. Barty2, K.R. Wilson2, I. Uschmann3, and E. Förster3 — 1Institut für Laser- und Plasmaphysik, Universität Essen, 45117 Essen, Germany — 2Department of Chemistry and Biochemistry, University of California at San Diego, CA 95616 La Jolla, USA — 3Institut für Optik und Quantenelektronik, Universität Jena, 07743 Jena, Germany
The rapid progress in the generation of intense femtosecond laser pulses during the past decade has provided new opportunities for producing short pulse, short wavelength radiation. Laser-driven radiation sources with picosecond or even femtosecond pulse widths and photon energies up to several MeV are now becoming available. These ultrashort X-ray pulses offer a unique combination of spatial and temporal resolution and thus make it possible to directly observe atomic motion, for example during chemical reactions or phase transitions. Using multi-keV (4.5keV and 8keV) X-ray pulses from femtosecond laser-produced plasmas we have performed time-resolved X-ray diffraction experiments at optically excited solid surfaces. We will disucss results on the extremely fast structural changes associated with non-thermal melting of semiconductors, and on the rapid dynamics of thermo-acoustic lattice distortions after short pulse laser excitation. Our results give clear experimental evidence that multi-keV X-ray pulses with sub-picosecond pulse duration can be obtained from femtosecond laser-produced plasmas.