Authors: Nahid Talebi Burcu Ögüt Wilfried Sigle Ralf Vogelgesang Peter A van Aken
Publish Date: 2014/06/06
Volume: 116, Issue: 3, Pages: 947-954
Abstract
Plasmonics is expected to play a key role in nanotechnology leading to intriguing routes in many engineering and biological applications Recently it has been realized that toroidal resonances could be an alternative to electric and magnetic resonances which have governed the innovation of plasmonic applications so far In a previous contribution we proved the existence of toroidal moments in an oligomeric voidplasmonic structure 1 In this article we investigate the role of topology and symmetry in decomposing the various dipolar quadrupolar and toroidal moments using energyfiltering transmission electron microscopy supported by threedimensional finitedifference timedomain method simulations The consequences of changing the topology on the toroidal character are discussed by comparing results obtained from nanoholes forming heptamer and hexamer nanocavity systems that were drilled into a thin silver filmWe acknowledge the support of U Eigenthaler and I Lakemeyer for the specimen preparation C T Koch for writing the scripts regarding the EFTEM acquisition and peak finding algorithm N Talebi acknowledges the AlexandervonHumboldt Foundation for financial support The research leading to these results has received funding from the European Union Seventh Framework Programme FP7/20072013 under Grant agreement no 312483 ESTEEM2
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