Gold–Silica–Gold Nanosandwiches: Tunable Bimodal Plasmonic Resonators

A metal–dielectric sandwich nanostructure, fabricated by a self-assembly technique, has a bimodal resonant response at optical frequencies due to dipolar plasmon hybridization (see picture). 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 altering the thickness of the dielectric spacer between the plasmonic components.