Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 15: Poster 1: Quanteninformation, Quanteneffekte, Laserentwicklung, Laseranwendungen, Ultrakurze Pulse, Photonik
Q 15.6: Poster
Montag, 14. März 2011, 16:30–19:30, P1
Kinetic description of laser-induced dielectric breakdown of insulators — •Nils Brouwer1, Oliver Brenk1, Helena Krutsch2, Dieter H. H. Hoffmann2, and Bärbel Rethfeld1 — 1Technische Universität Kaiserslautern, Deutschland — 2Technische Universität Darmstadt, Deutschland
Ultrashort laser pulses of high intensity are of increasing importance in material processing and fundamental research.
A proper understanding of the involved microscopic processes in condensed matter induced by laser irradiation is needed for enhanced controllability and to avoid damage to lenses. Transparent dielectrics may become opaque when being irradiated with intense laser beams, due to the creation of free electrons. We use the Boltzmann equation for a kinetic modelling of the microscopic collision processes determining the materials’ response. In order to investigate the change of optical parameters, like the dielectric function and the reflectivity, we extended a former model [1] by a dynamic calculation of the internal laser field. The contributions of impact ionization and strong electric field ionization to the total free electron density are calculated for fused silica. We trace dielectric breakdown initiated by the increasing free electron density. In addition, we calculate the energy transfer to the lattice obtaining a damage threshold for lattice melting.
A. Kaiser, B. Rethfeld, M. Vicanek and G. Simon,
Phys. Rev. B 61, 11437 (2000)