Gold-silica-gold nanosandwiches:: Tunable bimodal plasmonic resonators

The design and fundamental properties of metal-dielectric nanosandwiches arranged in a planar arrays on a solid support, are presented. The nanosandwiches are composed of three layers, two Au disks separated by a dielectric (SiO2) spacer. The degree of electromagnetic coupling in the system can be controlled by either varying the aspect ratio of one of the disks in the layered structure or by alerting the dielectric spacer between the plasmonic components. The characteristic dimensions of the system imply strong near-field interactions and an interpretation of the optical behavior in terms of hybridized dipolar-particle plasmons. The tunability of the system, together with the possibility of employing large-area substrates for fabrication of the nanostructures through self-assembly, represent vast potential in applications such as nanophotonics, optical biosensing, and metamaterials research.