Plasmonic interferences in two-dimensional stacked double-disk array

We numerically investigate the resonant spectral features of the two-dimensional stacked double-disk array. Narrow plasmon line shapes are observed on resonance spectra which are similar to the case of single-disk array. The electric field shows that the narrow plasmon modes are produced by the dark plasmon mode coupling to the diffraction which may be due to the retardation effect. The narrow mode and the dark mode overlap on resonance spectra, resulting in a Fano-like spectrum. The intensities of the electric fields for these narrow modes arising from the dark mode coupling are much stronger than that of the bright modes. (C) 2011 American Institute of Physics. [doi:10.1063/1.3583999]