Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 27: Time-Resolved Spectroscopy II

O 27.5: Vortrag

Dienstag, 26. Februar 2008, 12:15–12:30, MA 043

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

Non-equilibrium distribution functions of electron gas and phonon gas are calculated for metals irradiated with an ultrashort intense laser pulse. The excitation during femtosecond irradiation and the subsequent thermalization of the free electrons, as well as the dynamics of phonons can be described by a kinetic equation. The microscopic collision processes, such as absorption by inverse Bremsstrahlung, electron-electron, and electron-phonon interaction are considered with complete Boltzmann collision integrals. In contrast to aluminum, with a free-electron like conduction band considered in [1], the d-band in gold lies within the conduction band at about 2.5 eV below the Fermi surface of free electrons in s-band. Therefore, secondary electrons may be excited strongly, originating also from the d-band. We apply our kinetic approach to the case of gold by taking the electron density of states into account, and compare with the case of excitation of aluminum.

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