title: Edge Mode Coupling within a Plasmonic Nanoparticle.
abstract: The coupling of plasmonic nanoparticles can strongly modify their optical properties. Here, we show that the coupling of the edges within a single rectangular particle leads to mode splitting and the formation of bonding and antibonding edge modes. We are able to unambiguously designate the modes due to the high spatial resolution of electron microscopy-based electron energy loss spectroscopy and the comparison with numerical simulations. Our results provide simple guidelines for the interpretation and the design of plasmonic mode spectra.
authors.affiliation: Institute of Physics, University of Graz , 8010 Graz, Austria.|Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology , 8010 Graz, Austria.
authors.forename: Franz-Philipp
authors.initials: FP
authors.lastname: Schmidt
authors.affiliation: Institute of Physics, University of Graz , 8010 Graz, Austria.
authors.forename: Harald
authors.initials: H
authors.lastname: Ditlbacher
authors.affiliation: Institute of Physics, University of Graz , 8010 Graz, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hohenau
authors.affiliation: Institute of Physics, University of Graz , 8010 Graz, Austria.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hohenester
authors.affiliation: Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology , 8010 Graz, Austria.
authors.forename: Ferdinand
authors.initials: F
authors.lastname: Hofer
authors.affiliation: Institute of Physics, University of Graz , 8010 Graz, Austria.
authors.forename: Joachim R
authors.initials: JR
authors.lastname: Krenn
keywords: Plasmonics; electron energy loss spectroscopy; nanoparticles; transmission electron microscopy