Implementation of plasmonic band structure to understand polariton hybridization within metamaterials.

Gap surface plasmons (GSPs) serve a diverse range of plasmonic applications, including energy harvesting, communications, molecular sensing, and optical detection. GSPs may be realized where tightly spaced plasmonic structures exhibit strong spatial overlap between the evanescent fields. We demonstrate that within similar, nested geometries that the near-fields of the GSPs within the individual nanostructures are hybridized. This creates two or more distinct resonances exhibiting near-field distributions extended over adjacent spatial regions. In contrast, dissimilar, nested structures exhibit two distinct resonances with nominally uncoupled near-fields, resulting in two or more individual antenna resonance modes. We deploy plasmonic band structure calculations to provide insight into the type and degree of hybridization within these systems, comparing the individual components. This understanding can be used in the optimized design of polaritonic metamaterial structures for desired applications.