Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 65: Time-resolved spectroscopies III

O 65.6: Talk

Friday, March 27, 2009, 12:30–12:45, SCH A315

Kinetic Approach for Laser-excited Solids — •Banaz Omar and Baerbel Rethfeld — Technical University of Kaiserslautern, Department of Physics, Erwin Schroedinger Str. 46, D-67663 Kaiserslautern, Germany.

The microscopic dynamical processes for ultrashort laser-excited solids have been investigated theoretically. The transient non-equilibrium evolution of electron distribution function due to excitation and the subsequent thermalization of the free electrons, as well as the dynamics of phonons are studied in metals. The microscopic collision processes, such as inverse bremsstrahlung absorption, electron-electron collision and electron-phonon interaction are considered in the collision terms of Boltzmann equation [1]. We apply our kinetic approach to the case of gold by taking the total electron density of states into account. A free-electron like conduction band is considered in the d-band, which lies within the conduction band at about 2.5 eV below the Fermi surface. In the case of dielectrics, impact ionization and multi-photon ionization generate free electrons in the conduction band and holes in the valance band. Intense short laser-pulse change a cold solid to a hot dense plasma. With increasing free electron density a dynamical collision frequency is required for quasi-particle collisions.

[1] B. Rethfeld, A. Kaiser, M. Vicanek, and G. Simon, Phys. Rev. B 65, 214303 (2002)