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A: Fachverband Atomphysik

A 24: Atomic Clusters IV

A 24.4: Vortrag

Freitag, 12. März 2010, 11:45–12:00, F 303

Ionization dynamics of NaCl-nanocrystals in strong laser fields — •Christian Peltz¹, Thomas Fennel¹, Egill Antonsson², Burkhard Langer², Jürgen Plenge², and Eckart Rühl² — ¹Institut für Physik, Universität Rostock, Universitätsplatz 3, 18051 Rostock — ²Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin

Insight into the ultrafast ionization dynamics of dielectrics in intense laser fields is of major interest for laser-based nanomachining and dielectric damage. The time-scale and nature of the mechanisms governing material modification and energy deposition, such as avalanche breakdown effects and plasma heating, are of central importance for realizing well-controlled material damage [1]. As finite and scalable gas phase model systems for solid dielectrics, NaCl-nanocrystals are promising systems to explore the time- and size-dependence of the coupling process. Experiments on these systems show pronounced pump-probe effects in the ion and electron emission with moderate laser intensities (∼10¹³W/cm²). To investigate the microscopic ionization dynamics in such multi-component system we apply molecular dynamics simulation originally developed for intense laser-cluster interactions [2]. The simulation results, which are in good agreement with the experimental findings, reveal that avalanche-like metallization of the nanocrystals and resonant collective electron heating are the key to explain the observed timing effects on the ionization dynamics.

[1] L. Englert et al., Appl. Phys. A 92, 749 (2008)

[2] T. Fennel et al., Phys. Rev. Lett. 99, 233401 (2007)