title: From isolated metaatoms to photonic metamaterials: evolution of the plasmonic near-field.
abstract: Metamaterials are artificial media which can provide optical properties not available from natural materials. These properties often result from the resonant excitation of plasmonic modes in the metallic building blocks ("metaatoms") of the metamaterial. Electromagnetic interactions between the metaatoms significantly modify the resonances of the individual metaatoms and influence the optical properties of the whole metamaterial. To better understand these interactions, we study in this Letter the evolution of the plasmonic near-field in the course of the transition from an isolated metaatom, in our case a split-ring resonator (SRR), to a photonic metamaterial via electron energy-loss spectroscopy. For small SRR ensembles, we observe the formation of discrete optical bright and dark modes due to coupling of the metaatoms. Large SRR arrays reveal a quasi-continuum of modes in the interior and distinct edge modes at the boundaries of the array. Our experimental results are in excellent agreement with numerical calculations.
authors: Physikalisches Institut, Universität Bonn, Nussallee 12, D-53115 Bonn, Germany. voncube@uni-bonn.de
authors: Felix
authors: F
authors: von Cube
authors: Stephan
authors: S
authors: Irsen
authors: Richard
authors: R
authors: Diehl
authors: Jens
authors: J
authors: Niegemann
authors: Kurt
authors: K
authors: Busch
authors: Stefan
authors: S
authors: Linden