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K: Fachverband Kurzzeit- und angewandte Laserphysik
K 3: Laser Systems and Applications
K 3.4: Vortrag
Dienstag, 6. März 2018, 15:00–15:15, MB HS
High fluence femtosecond laser ablation of molybdenum targets — •Julian Wegner1, Dongye Zhao2,3, Niels Gierse3, Marcin Rasinski3, Sebastijan Brezinsek3, Georg Pretzler1, Honging Ding2, and Christian Linsmeier3 — 1Institut für Laser- und Plasmaphysik, Heinrich Heine Universität Düsseldorf, Germany — 2Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams, Dalian University of Technology, Dalian, P R China — 3Institut für Energie- und Klimaforschung - Plasmaphysik, Forschungszentrum Jülich GmbH, Germany
We present experimental data on the ablation of molybdenum targets by femtosecond laser pulses over five orders of magnitude in laser fluence. The experiments were performed with a Ti:Sa laser with sub 7 fs (FWHM) laser pulses and a pulse energy of 0.4 mJ illuminating flat Mo targets. The samples were analyzed post mortem by electron microscopy concerning surface morphology and ablation rate. Furthermore, cross-section images in the craters were taken by focused ion beam technique, yielding information on the structure of the remaining bulk. This analysis gives a detailed overview on ablation with laser fluences along many orders of magnitude. Five distinct regimes are identified by this analysis. Four of them – with lower laser fluence – are compared to models in the literature. The fifth regime with laser fluences up to 6000 J/cm2 has not been described before. We present a new model to explain this new ablation regime.