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K: Fachverband Kurzzeitphysik

K 2: Poster I - Laseranwendungen

K 2.5: Poster

Montag, 19. März 2007, 16:30–18:30, Poster A

Control of ionization processes in high band gap materials via tailored femtosecond laser pulses — •Lars Englert¹, Bärbel Rethfeld², Lars Haag¹, Cristian Sarpe-Tudoran¹, Matthias Wollenhaupt¹, and Thomas Baumert¹ — ¹Universität Kassel, Institut für Physik und CINSaT, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany — ²Gesellschaft für Schwerionenforschung mbH, Planckstr. 1, D-64291 Darmstadt, Germany

Femtosecond laser ablation in combination with pulse shaping techniques is a powerful resource to take control over the energy deposition process into the material.

We present a systematic study of laser ablation of dielectrica with tailored femtosecond pulses. The pulse shaping is done by spectral phase modulation and a modified microscope setup is used to focus the pulses onto fused silica or sapphire samples. Post-mortem SEM and AFM analysis shows reproduceable structures more than one order of magnitude smaller than the diffraction limit.

Generation of free electrons by multiphoton and avalanche ionization is the initial step needed for ablation of dielectrics. By tailoring the temporal profile of the pulse we can favour one ionization mechanism over the other. This is also supported by preliminary theoretical simulations.