Berlin 2005 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 34: Poster
DY 34.42: Poster
Montag, 7. März 2005, 15:30–18:00, Poster TU D
Self-organised pattern formation upon femtosecond laser ablation: circular polarisation — •Olga Varlamova1,2, Florenta Costache1,2, Michael Bestehorn1, and Jürgen Reif1,2 — 1Brandenburgische Technische Universität Cottbus — 2IHP/BTU JointLab
Upon multi-shot femtosecond laser ablation from different materials, self-organised regular patterns are observed at the crater bottom. For linearly polarised excitation, it has been shown that long periodic ripples develop, the orientation of which is determined by the polarisation direction, though the fundamental nature of this correlation is not yet known.
To investigate this phenomenon closer, we performed corresponding experiments using circularly polarised light. Scanning-Electron and Atomic-Force microscopy reveal that, again, a variety of self-organised patterns is obtained, from bead-string and skin-like structures to bifurcating longer lines. The orientation of these lines, however, is random and varies between different spots. First attempts are made to model this behaviour.