Plasmonic superlattices: Hierarchical subwavelength hole arrays

This Letter describes the dispersion properties of plasmonic lattices consisting of near-infinite arrays and superlattices (patches) of nanoholes in thin gold films. Zero-order, optical transmission spectra of the plasmonic lattices revealed that compared to the near-infinite arrays, the superlattices showed new resonances that depended on the separation between patches. Theoretical calculations were in good agreement with the measurements and identified the origins of the additional transmission peaks. Surface plasmon dispersion diagrams were also measured, and the superlattices were found to exhibit satellite-bands around the primary (intra-patch) surface plasmon polariton modes that were not present in the near-infinite nanohole arrays.