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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.72: Poster

Donnerstag, 27. März 2003, 15:30–18:00, P1

Pattern formation upon femtosecond laser ablation of transparent dielectrics — •Ionut Georgescu¹, Michael Bestehorn¹, Florenta Costache², and Jürgen Reif² — ¹LS Theoretische Physik II, Statistische Physik und Nichtlineare Dynamik, Brandenburgische Technische Universität Cottbus, Erich-Weinert-Str 1, 03046 Cottbus, Germany — ²LS Experimentalphysik II, Brandenburgische Technische Universität Cottbus, Universitätsplatz 3-4, 03044 Cottbus, Germany

By means of a 2D partial differential equation of Kardar-Parisi-Zhang type, we model a series of ripples, found on femtosecond laser ablation of wide band gap insulators (BaF₂, CaF₂). Studies of the ablated crater have shown a complex surface structure of ripples in nanometer range, perpendicular on the beam polarization. Recent experiments have proved that they do not obey the classical idea of an interference pattern translating into ripples. They were found to originate from a Coulomb explosion of the positively charged surface. A self-organizing relaxation of the non-equilibrium surface is therefore assumed to be responsible for the structures.