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O: Fachverband Oberflächenphysik
O 18: Plasmonics and Nanooptics II
O 18.7: Vortrag
Montag, 14. März 2011, 18:45–19:00, PHY C213
Plasmonic oligomers: the role of individual particles on collective behavior — •Mario Hentschel1,2, Na Liu3, and Harald Giessen1 — 14th Physics Institute and Research Center SCoPE, University of Stuttgart, D-70569 Stuttgart, Germany — 2Max-Planck-Institute for Solid State Research, Heisenbergstr. 1, D-70569 Stuttgart, Germany — 3Department of Chemistry, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
We theoretically and experimentally study the transition from isolated to collective modes in plasmonic oligomers which consist of a six-particle outer ring around a single center particle. The inter-particle gap distance plays a key role for the formation of collective modes. The plasmon hybridization method is applied to analyze the optical properties of plasmonic oligomers. The interference between a subradiant and a superradiant mode leads to a pronounced Fano resonance [1]. Furthermore we demonstrate the possibility to switch on and off the Fano resonance by the presence or absence of the central nanoparticle without breaking the system symmetry [2]. We also study the optical response upon modifications such as the introduction of defects by shifting the inner particle from the center position and the variation of the number of individual discs. The ability to observe and tune the collective resonances in metallic nanostructures will allow for the creation of a rich new set of artificial plasmonic molecules with a wide range of controlled optical properties. [1] B. Lukyanchuk et al., Nature Mat. 9, 707 (2010) [2] M. Hentschel et al., Nano Lett. 10, 2721 (2010)