Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Poster Session I (Semiconductor Substrates: Epitaxy and growth; Semiconductor Substrates: Adsorbtion; Semiconductor Substrates: Solid-liquid interfaces; Semiconductor Substrates: Clean surfaces; Oxides and insulators: Epitaxy and growth; Oxides and insulators: Adsorption; Oxides and insulators: Clean surfaces; Organic, polymeric and biomolecular films - also with adsorbates; Organic electronics and photovoltaics, Surface chemical reactions; Heterogeneous catalysis; Phase transitions; Particles and clusters; Surface dynamics; Surface or interface magnetism; Electron and spin dynamics; Spin-Orbit Interaction at Surfaces; Electronic structure; Nanotribology; Solid/liquid interfaces; Graphene; Others)
O 41.68: Poster
Dienstag, 23. März 2010, 18:30–21:00, Poster B1
Design and operation of a microscopy setup for optical second harmonic generation — •Gerson Mette1, Kristina Klass1, Michael Dürr1,2, Jens Güdde1, and Ulrich Höfer2 — 1Fachbereich Physik und Zentrum für Materialwissenschaften, Philipps-Universität Marburg, D-35032 Marburg — 2Fakultät Angewandte Naturwissenschaften, Hochschule Esslingen, D-73728 Esslingen
Laser-induced processes like desorption or diffusion often show a strong non-linear dependence on laser fluence. As a consequence, the desorption- or diffusion-rates differ strongly for different areas of the excited surface because of the laser's beam profile.
We present a setup for spatially resolved optical second-harmonic generation (SHG), i.e. SHG-microscopy, and illustrate its operation on the basis of our time-domain study of laser-induced diffusion of oxygen on a vicinal Pt(111) surface at low substrate temperature. Femtosecond laser pulses excite not only the diffusion of oxygen on the surface itself but also generate the second-harmonic light which is detected spatially resolved by an intensified CCD camera. Magnification of the area of interest on the sample to the CCD chip is achieved by a commercial camera lens. The fluence dependence of the diffusion process can be measured in real space across the laser's beam profile. In combination with a two-pulse correlation experiment, the fluence dependence of the energy transfer time between electronic and adsorbate system can be investigated in the same way.