Dresden 2006 – wissenschaftliches Programm
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O: Oberflächenphysik
O 18: Nanostructures II
O 18.6: Vortrag
Dienstag, 28. März 2006, 12:30–12:45, PHY C213
Excitation of surface plasmon polaritons at surface grooves in bulk metals and thin film metal waveguides — •J. Renger1, S. Grafström1, J. Seidel1, P. Olk1, L.-M. Eng1, C. Akhmadaliev2, L. Bischoff2, B. Schmidt2, D. Taverna3, and J.-C. Weeber3 — 1Institute for Applied Photophysics, University of Technology Dresden, D-01062 Dresden, Germany — 2Forschungszentrum Rossendorf, Institute of Ion Beam Physics and Materials Research, D-01314 Dresden, Germany — 3Laboratoire de Physique de l’Université de Bourgogne, UMR CNRS 5027, F-21078 Dijon, France
We explore different approaches to excite surface plasmon polaritons (SPPs), aiming at strong enhancement and localization of the electromagnetic field. The SPP is excited by focussing laser light onto a small single groove or a grating having a finite number of periods. Such grooves cancel the requirement of momentum conservation, and makes the excitation of surface waves possible. The metallic structures were fabricated by high resolution focused ion beam milling (25 keV Ga+, IMSA-Orsay Physics FIB) into photolithographic pre-patterned 60 nm thick aluminium thin-film metallic waveguides. Our multiple multipole calculations show a characteristic dependence on both the width and the depth of the grooves, as well as a strong impact of the angle of incident laser light. Hence, this allows the selective excitation of SPP modes propagating at the air/metal or metal/glass interface. Experimental observation of SPPs was performed using scanning near-field optical microscopy with uncoated etched fiber probes. These results confirm the excitation of SPP modes at grooves.