Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 33: Nanostructures at Surfaces: Metals, Oxides and Semiconductors I

O 33.1: Vortrag

Dienstag, 21. März 2017, 10:30–10:45, REC/PHY C213

Two-color excitation of image potential states and above threshold ionization at gold nanotips — •Thomas Quenzel, Jörg Robin, Jan Vogelsang, Andreas Wöste, Petra Groß, and Christoph Lienau — Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg

Metallic nanotapers give access to strong field phenomena at a single solid-state nanostructure [1-3]. Experiments on bulk solid-state systems have established the existence of surface states by two photon photoemission experiments [4]. Here we use femtosecond two-color photoemission from a home-built NOPA to study the excitation and the dynamics of image potential states on a metallic nanotip.

We measure kinetic energy spectra of the photoemitted electrons as a function of delay between the (visible) pump pulse and the (near-infrared) probe pule. Atomic-like above-threshold ionization spectra are observed, which indicate the excitation of long-lived, weakly bound states at the surface of the nanostructure. With the presented work we take a step towards the emission of cold electron pulses as a promising source for ultrafast electron microscopy.

[1]Herink, Nature 483, 190-193 (2012),[2]Krüger, Nature 475, 78 (2011),[3]Piglosiewicz, Nat. Photon. 9, 37 (2014),[4]Höfer, Science 277, 1480 (1997)