Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 14: Poster session I (Adsorption, Epitaxy and growth, Phase transitions, Surface reactions, Organic films, Electronic structure, Methods) (sponsored by Omicron Nanotechnology GmbH)

O 14.76: Poster

Montag, 27. März 2006, 18:00–21:00, P2

Non-linear Photoemission Electron Microscopy on silver islands by use of frequency doubled fs-laser pulses — •Jawad Slieh, Ulf Kleineberg, and Ulrich Heinzmann — Molecular and Surface Physics, University of Bielefeld, Germany

Multiphoton photoemission from nanosized silver islands evaporated on silicon wafer substrates has been studied using of a Photoemission Electron Microscope (PEEM) coupled to a frequencydoubled Ti:Sa system. The fs-laser pulses generated by the Ti:Sa oscillator (77 MHz repetition rate) exhibit a pulse duration of 30-50 fs, a pulse energy of 3nJ and a center photon energy of 3.1 eV. This photon energy is lower than the work function of silver (4.6 eV) and thus no linear photoemission takes place. Furthermore, linear photoemission from the same samples has been investigated by illumination with light from a mercury discharge source (4.9 eV). The experimental results are compared and discussed in terms of the shape and size dependence of the multiphoton photoemission process.