Regensburg 2007 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 39: Nanostructures at Surfaces IV (Dots, Particles, Clusters, Arrays)

O 39.1: Vortrag

Mittwoch, 28. März 2007, 15:45–16:00, H36

Investigation of the scattering form factor and surface plasmon resonances of metallic nanoparticles by Bragg diffraction — •Manuel Gonçalves, André Siegel, Ralf Ameling, and Othmar Marti — University of Ulm, Inst. Experimental Physics, Albert-Einstein-Allee 11, D-89069 Ulm, Germany

Plasmon resonances in particles of triangular shape on surfaces were investigated by experimental far-field methods and by numerical simulations. The spectral location of these resonances and the associated near-field enhancements are of high relevance for applications like surface enhanced Raman scattering (SERS) and other nonlinear effects. However, these resonances depend on many parameters, like size and shape of the particles, material and illumination conditions. On the other hand, the surface plasmon resonances influence directly the scattering of light, which can be measured in far-field.

The light scattering form factor of particles of different shapes was investigated by measuring the Bragg diffraction patterns of arrays of identical nanoparticles. The relative intensity of the Bragg diffraction orders is very sensitive to the shape and material of the particles. Thus, theoretical models of the scattering form factors of the particles can be checked by simulation of the Bragg patterns and comparison with the experimental data. This method relies on the averaged form factor of the particles and is not sensitive to particular features of single particles.