Hannover 2003 – wissenschaftliches Programm

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A: Atomphysik

A 17: Postersitzung 2

A 17.13: Poster

Donnerstag, 27. März 2003, 16:00–18:30, Poster

Crystal layers in extremely intense laser pulses: Dynamics and x-ray generation — •Karen Z. Hatsagortsyan and Christoph H. Keitel — Theoretische Quantendynamik, Fakultät für Physik, Universität Freiburg, H.-Herder-Str. 3, D-79104 Freiburg, Germany

The interaction of a short intense laser pulse with a thin solid crystal layer is considered with emphasis on coherent x-ray generation [1]. For a selective range of parameters the initial regular structure of a thin layer is preserved during the short interaction. In one regime with the transversal oscillation amplitude of the electron in the laser field exceeding the layer transversal width, the electrons are extracted from the layer due to the extreme force. After excursion through free space they penetrate periodically through the ionic structure. Thousands of harmonics of the laser radiation field are shown to coherently amplify along the interaction length [1], the gain being competative with that of leading x-ray sources [2]. In another regime of laser-crystal parameters, the high index of refraction of the medium along with its regularity can lead to phase matching between the fundamental and high harmonic waves being generated in this case mainly by the tunneling-recollision mechanism. We predict very high temporal and spatial coherence of the radiation in the hard x-ray domain [1]. 2D-PIC simulations with moving ions are finally employed to display the crystal dynamics.

[1] K.Z. Hatsagortsyan and C.H. Keitel, Phys. Rev. Lett. 86, 2277 (2001) and J. Phys. B 35, L175 (2002).

[2] R.C. Elton, X-ray lasers (Academic Press, London, 1990); D. Guiletti and L.A. Gizzi, Riv. Nuov. Cim. 21, 1 (1998).