title: Atomic-scale confinement of resonant optical fields.
abstract: In the presence of matter, there is no fundamental limit preventing confinement of visible light even down to atomic scales. Achieving such confinement and the corresponding resonant intensity enhancement inevitably requires simultaneous control over atomic-scale details of material structures and over the optical modes that such structures support. By means of self-assembly we have obtained side-by-side aligned gold nanorod dimers with robust atomically defined gaps reaching below 0.5 nm. The existence of atomically confined light fields in these gaps is demonstrated by observing extreme Coulomb splitting of corresponding symmetric and antisymmetric dimer eigenmodes of more than 800 meV in white-light scattering experiments. Our results open new perspectives for atomically resolved spectroscopic imaging, deeply nonlinear optics, ultrasensing, cavity optomechanics, as well as for the realization of novel quantum-optical devices.
authors.affiliation: Nano-Optics & Biophotonics Group, Experimentelle Physik 5, Physikalisches Institut, Röntgen Research Center for Complex Materials (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Kern
authors.forename: Swen
authors.initials: S
authors.lastname: Grossmann
authors.forename: Nadezda V
authors.initials: NV
authors.lastname: Tarakina
authors.forename: Tim
authors.initials: T
authors.lastname: Häckel
authors.forename: Monika
authors.initials: M
authors.lastname: Emmerling
authors.forename: Martin
authors.initials: M
authors.lastname: Kamp
authors.forename: Jer-Shing
authors.initials: JS
authors.lastname: Huang
authors.forename: Paolo
authors.initials: P
authors.lastname: Biagioni
authors.forename: Jord C
authors.initials: JC
authors.lastname: Prangsma
authors.forename: Bert
authors.initials: B
authors.lastname: Hecht
mesh_terms: D019281:Dimerization; D004574:Electromagnetic Fields; D006046:Gold / Q000737:chemistry; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes; D055095:Optics and Photonics; D011789:Quantum Theory; D012542:Scattering, Radiation; D013053:Spectrophotometry / Q000379:methods
chemical_list: D006046:Gold