Mainz 2017 – scientific programme
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A: Fachverband Atomphysik
A 39: Clusters III (with MO)
A 39.6: Talk
Friday, March 10, 2017, 16:00–16:15, N 3
Tracing strong-field processes in nanoparticles in real time — •Bernd Schütte1, Björn Thorben Kruse2, Christian Peltz2, Marc J. J. Vrakking1, Arnaud Rouzée1, and Thomas Fennel1,2 — 1Max-Born-Institut, Berlin — 2Universität Rostock
Strong-field ionization of solid-density targets is fundamentally different from strong-field ionization of atoms, and can result in highly efficient absorption of laser energy. In order to understand fundamental strong-field phenomena, the investigation of isolated nanoparticles is advantageous, as energy is not dissipated into the environment, allowing one to focus on the primary laser-matter coupling mechanisms.
Here we trace the charging of Ar and Xe nanoparticles directly in the time domain by applying the recently developed ionization ignition method [1]. Seed electron generation by an intense XUV pulse allows us to temporally control the heating and ionization induced by a 1.5-ps NIR pulse, whose intensity (I=1.5× 1013 W/cm2) is not sufficient to ionize neutral clusters. Surprisingly, we find that highly charged ions up to Xe15+ are produced. The average ion charge state increases exponentially during the rising edge of the NIR pulse, which is the first real-time observation of ionization avalanching. The experimental results will be compared with molecular dynamics calculations.
Our method provides new perspectives for the time-resolved investigation of strong-field phenomena in nanostructures, liquids and solids. It could e.g. be used to record the ablation of material in real time, which is relevant for practical applications such as laser machining.
[1] B. Schütte et al., Phys. Rev. Lett. 116, 033001 (2016).