title: Revealing Nanostructures through Plasmon Polarimetry.
abstract: Polarized optical dark-field spectroscopy is shown to be a versatile noninvasive probe of plasmonic structures that trap light to the nanoscale. Clear spectral polarization splittings are found to be directly related to the asymmetric morphology of nanocavities formed between faceted gold nanoparticles and an underlying gold substrate. Both experiment and simulation show the influence of geometry on the coupled system, with spectral shifts Δλ = 3 nm from single atoms. Analytical models allow us to identify the split resonances as transverse cavity modes, tightly confined to the nanogap. The direct correlation of resonance splitting with atomistic morphology allows mapping of subnanometre structures, which is crucial for progress in extreme nano-optics involving chemistry, nanophotonics, and quantum devices.
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Marie-Elena
authors.initials: ME
authors.lastname: Kleemann
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Jan
authors.initials: J
authors.lastname: Mertens
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.|Laboratory of Solid State Physics and Magnetism, KU Leuven , Celestijnenlaan 200D, BUS 2414, Leuven 3001, Belgium.
authors.forename: Xuezhi
authors.initials: X
authors.lastname: Zheng
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Sean
authors.initials: S
authors.lastname: Cormier
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Turek
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Felix
authors.initials: F
authors.lastname: Benz
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Rohit
authors.initials: R
authors.lastname: Chikkaraddy
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: William
authors.initials: W
authors.lastname: Deacon
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Anna
authors.identifier: 0000-0003-2547-0124
authors.initials: A
authors.lastname: Lombardi
authors.affiliation: Laboratory of Solid State Physics and Magnetism, KU Leuven , Celestijnenlaan 200D, BUS 2414, Leuven 3001, Belgium.
authors.forename: Victor V
authors.initials: VV
authors.lastname: Moshchalkov
authors.affiliation: Department of Electrical Engineering (ESAT-TELEMIC), KU Leuven , Kasteelpark Arenberg 10, BUS 2444, Leuven 3001, Belgium.
authors.forename: Guy A E
authors.initials: GA
authors.lastname: Vandenbosch
authors.affiliation: NanoPhotonics Centre, Cavendish Laboratory, University of Cambridge , Cambridge, CB3 0HE, United Kingdom.
authors.forename: Jeremy J
authors.identifier: 0000-0002-9606-9488
authors.initials: JJ
authors.lastname: Baumberg
keywords: nano-optics; nanoparticles; plasmonic cavities; plasmonic polarization signature; tunable plasmons