Open AccessUnderstanding near/far-field engineering of optical dimer antennas through geometry modification
Author(s) -
Wei Ding,
Renaud Bachelot,
R. Espiau de Lamaëstre,
Demetrio Macı́as,
Anne-Laure Baudrion,
Pascal Royer
Publication year - 2009
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.17.021228
Subject(s) - antenna (radio) , dimer , near and far field , optics , field (mathematics) , geometry , plasmon , wavelength , resonance (particle physics) , materials science , physics , telecommunications , computer science , mathematics , nuclear magnetic resonance , atomic physics , pure mathematics
Numerical investigations based on the boundary element method (BEM) have been carried out to two-dimensional (2-D) silver dimer nano-antennas of various geometries. The near-field and far-field properties are mainly determined by the local geometry at the gap and the global shape of the antenna shafts respectively. A hybrid dimer antenna, which mixes the geometry ingredients of the rod dimer and the bowtie, benefits in both near and far field. Using a microcavity representation, the resonance in dimer nano-antennas is explained in a common and semi-analytical manner. The plasmonic enhancement and the wavelength mismatching in the optical dimer antenna are naturally embodied in this model. The quality factor of the resonance, which can be influenced by the wavelength and the geometry, is discussed intuitively. The understanding presented in this work could guide the future engineering of the optical dimer antenna.