Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 1: Tutorial: Attosecond Electron Dynamics

HL 1.2: Tutorium

Sonntag, 25. März 2012, 16:40–17:15, EW 201

Control of Electron Emission from Nanoscopic Systems by Ultrashort Laser Pulses — •Eckart Rühl — Physikalische Chemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin, Germany

Recent progress in control of electron emission from nanoscopic dielectric systems by ultrashort laser pulses and related work is reviewed. Coherent control strategies of laser-induced processes of gas phase species have been established before. Such gas phase species are not limited to atoms, molecules, or clusters. More recently it has been shown that intense nanoparticle beams can be prepared in narrow size distributions as gas phase targets. Ultrashort, intense, and carrier envelope phase-stabilized laser pulses of 4-6 fs in the near infrared regime lead to novel electron emission processes as well as the control of electron motion in the attosecond time regime. This goes beyond well-known photoemission induced by one-photon absorption of ionizing radiation, where the electron spectra of nanoparticles and macroscopic condensed matter are dominated by low kinetic energy, inelastically scattered electrons. In contrast, few-cycle laser pulses yield electron spectra with phase-dependent emission of high kinetic energy electrons. This process has been shown to be unique for condensed matter and is not possible for atomic species. Details of the processes occurring on ultra-short time scales have been assigned by using semiclassical Monte-Carlo simulations. These results indicate that tunnel ionization, the laser field, dielectric near-field enhancement, and the Coulomb field of the liberated charges contribute. Prospects of these results are briefly discussed.