Authors: Dr. ir. Xuezhi Zheng, Prof. dr. ir. Guy A. E. Vandenbosch, Prof. Dr. Victor V. Moshchalkov
Source: FERMAT, Volume 9, Communications 6, May Jun., 2015
Abstract: Symmetry holds a prominent position in defining the optical response of a nanoantenna. In this work, we harness a mathematical tool, group representation theory, combine it with the eigenmode analysis for a nanoantenna, and illustrate how the symmetry allows or forbids the energetic coupling (i.e., interference) between a nanoantenna's eigenmodes. We do this especially using a nanobar structure and a symmetric cross structure. Further, the consequence of symmetry-breaking is illustrated by an asymmetric cross-shaped nanostructure, i.e., a strong asymmetric Fano-type resonance line shape due to mode interference is observed with the physics behind elaborated. Both numerical and experimental evidences are provided
Keywords: Eigenmodes, group theory, mode interference and Fano resonance, nanoantennas, symmetry/symmetry breaking, volumetric integral equation (VIE).
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