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A: Fachverband Atomphysik

A 7: Metal clusters

A 7.6: Talk

Tuesday, March 11, 2008, 12:30–12:45, 3D

Directed Emission of Fast Electrons from Excited Metal Nanoparticles — •Johannes Passig, Thomas Fennel, Nguyen Xuan Truong, Josef Tiggesbäumker, and Karl-Heinz Meiwes-Broer — Universität Rostock, Institut für Physik, Universitätsplatz 3, 18051-Rostock, Germany, www.physik.uni-rostock.de/cluster

Experimental studies on laser excited silver particles reveal a strong asymmetric electron emission characteristic giving electron kinetic energies of up to 1.3 keV in the direction of the laser polarization axis. It could be shown that in a dual pulse experiment the evolution of the plasmon frequency following the pump pulse enables resonant excitation by the probe pulse. The resulting electron energies, gained in the nanometer scaled microplasma, as well as the spatial asymmetry in emission direction cannot be explained by a conventional hydrodynamical or a purely coulomb driven expansion process.

We present a novel acceleration mechanism through plasmon assisted, phase-matched electron-cluster rescattering (SPARC) [1], which is capable to explain the generation of a directed emission of high energy electrons obtained in the experiment. Moreover, Vlasov simulations show that an attosecond electron pulse train is generated.

[1] Th. Fennel, T. Döppner, J. Passig, Ch. Schaal, J. Tiggesbäumker, and K.-H. Meiwes-Broer, Phys. Rev. Lett. 98, 143401 (2007)