Plasmons in coupled voids

Plasmons in structured metallic systems have attracted considerable attention over the last few years as promising candidates to realize plasmon guiding, plasmon amplification, and in general, optical components at the nanoscale. Examples of these systems are chains of nanoparticles, where <50 nm particles are coupled to guide their Mie-like plasmons and the small size of the particles is chosen to minimize radiative losses. Void cavities have been also investigated in the context of inverted opals. Here, we investigate the optical properties of systems formed by dielectric nanoinclusions in a metal. Radiative losses in this type of system are prevented by total confinement of the light inside the dielectric, from where it cannot propagate beyond the metal skin depth. This allows considering larger void sizes and achieving larger propagation distances. Our results are based upon solution of Maxwell's equations using the boundary element method for systems consisting of two or more dielectric inclusions, including overlapping systems.