title: Nested plasmonic resonances: extraordinary enhancement of linear and nonlinear interactions.
abstract: Plasmonic resonators can provide large local electric fields when the gap between metal components is filled with an ordinary dielectric. We consider a new concept consisting of a hybrid nanoantenna obtained by introducing a resonant, plasmonic nanoparticle strategically placed inside the gap of an aptly sized metallic antenna. The system exhibits two nested, nearly overlapping plasmonic resonances whose signature is a large field enhancement at the surface and within the bulk of the plasmonic nanoparticle that leads to unusually strong, linear and nonlinear light-matter coupling.
authors.forename: Domenico
authors.initials: D
authors.lastname: de Ceglia
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Vincenti
authors.forename: Neset
authors.initials: N
authors.lastname: Akozbek
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Bloemer
authors.forename: Michael
authors.initials: M
authors.lastname: Scalora