title: Diabolo nanoantenna for enhancing and confining the magnetic optical field.
abstract: In this Letter, we introduce a new nanoantenna concept aimed at generating a single magnetic hot spot in the optical frequency range, thus confining and enhancing the magnetic optical field on the background of a much lower electric field. This nanoantenna, designed by applying Babinet's principle to the bowtie nanoaperture, takes the shape of a diabolo. It differs from the well-known bowtie nanoantenna in that the opposing pair of metal triangles are electrically connected through their facing tips. Thus instead of a large charge density accumulating at the air gap of the bowtie nanoantenna, leading to a large electric field, a high optical current density develops within the central "metal gap" of the diabolo nanoantenna, leading to a large magnetic field. Numerical simulation results on the first nanodiabolo geometries show a 2900-fold enhancement of the magnetic field at a wavelength of 2540 nm, confined to a 40-by-40 nm region near the center of the nanoantenna.
authors.affiliation: Department of Optics, FEMTO-ST Institute, UMR CNRS 6174, University of Franche-Comté, Besançon, France. thierry.grosjean@univ-fcomte.fr
authors.forename: T
authors.initials: T
authors.lastname: Grosjean
authors.forename: M
authors.initials: M
authors.lastname: Mivelle
authors.forename: F I
authors.initials: FI
authors.lastname: Baida
authors.forename: G W
authors.initials: GW
authors.lastname: Burr
authors.forename: U C
authors.initials: UC
authors.lastname: Fischer