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K: Kurzzeitphysik

K 4: Kurzzeitphysik-Poster

K 4.4: Poster

Mittwoch, 20. März 2002, 17:40–18:40, HZO 80

Time-resolved x-ray diffraction experiments using a femtosecond laser-plasma keV x-ray source — •C. Blome, K. Sokolowski-Tinten, C. Dietrich, A. Tarasevitch, J. Blums, M. Horn von Hoegen, and D. von der Linde — Institute for Laser and Plasmaphysics, University of Essen, Universitätsstr. 5, 45117 Essen, Germany

Ultrashort x-ray pulses offer a unique combination of atomic-scale spatial and temporal resolution, which permits direct measurements of structural transients on an ultrafast time scale. Using time-resolved x-ray diffraction with femtosecond, multi-keV x-ray pulses from a laser-produced plasma we have studied transient lattice dynamics in optically excited Germanium and Bismuth. Our experiments on Germanium demonstrate non-thermal melting within a few hundred femtoseconds and a sub-300 fs x-ray pulse duration at 4.5 keV [1]. In Bismuth measurements of the transient behavior of two different diffraction orders ((111) and (222)) gave clear evidence that the strong excitation of A1g optical phonons occurs prior to disordering and melting of the material. [1] Phys.Rev.Lett 87,225701 (2001)