Regensburg 2007 – scientific programme
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O: Fachverband Oberflächenphysik
O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)
O 17.14: Poster
Monday, March 26, 2007, 17:30–20:30, Poster C
Influence of pulsed laser light on gold triangles: Experiment vs. theory — •Andreas Kolloch1, Juliane König-Birk1, Kevin Shuford2, George Schatz2, Paul Leiderer1, and Johannes Boneberg1 — 1Fachbereich Physik, Universität Konstanz, Fach M676, 78457 Konstanz — 2Chemistry Department, Northwestern University
The optical properties of nanostructures are a topic of considerable current interest. In analogy to the near-fields around a Hertz dipole one expects in the optical range similar near-fields in the surrounding of nanostructures when they are illuminated with light. To visualize these near-fields we use a method called "optical near-field photography". In our experiments we use e.g. silicon as substrate. The nanostructures, in this case gold triangles, on the substrate are illuminated with femtosecond laser pulses. The intensity is adjusted such that no influence of the illumination is detectable on the bare substrate. In the vicinity of the nanostructures, however, local ablation of the substrate is observed due to the intensity enhancement in the optical near-field. The resulting field distribution patterns depend on both the polarization of the laser light and the size of the triangles, as well as the arrangement of the nanostructures in the case of periodic arrays. A comparison with simulations shows qualitative agreement, but also some discrepancies with the experiments.