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O: Oberflächenphysik

O 18: Nanostructures II

O 18.4: Vortrag

Dienstag, 28. März 2006, 12:00–12:15, PHY C213

In-situ Monitoring of Particle Plasmon Excitation in Ag-nanostructures — •Liviu I. Chelaru, Dagmar Thien, Michael Horn-von Hoegen, and Frank Meyer zu Heringdorf — Institut für Experimentelle Physik, Universität Duisburg-Essen, Duisburg, Germnany

Although the Mie-Plasmon in Ag islands and particles is well known, it is still a challenge to analyze the plasmonic behaviour of single Ag particles and nanowires on surfaces. Photoemission Microscopy offers a way to directly observe particle plasmons by means of two photon photoemission. Here, the plasmon as an intermediate state completely dominates the photoemission signal; a first photon is used to excite a particle plasmon before a second photon triggers the plasmon-assisted photoemission. We will show, that the particle plasmon evolves during growth of Ag islands and wires on 4 degree vicinal Si(001) and demonstrate that depending on the size of the particle only distinct plasmon modes can be excited. The strong nonlinear nature of the two-photon photoemission process allows to image the fringe field pattern around the particle on the surface and to directly correlate the particle plasmon excitation with the lateral dimensions of the particle.