title: Directional Light Extinction and Emission in a Metasurface of Tilted Plasmonic Nanopillars.
abstract: Plasmonic optical antennas and metamaterials with an ability to boost light-matter interactions for particular incidence or emission angles could find widespread use in solar harvesting, biophotonics, and in improving photon source performance at optical frequencies. However, directional plasmonic structures have generally large footprints or require complicated geometries and costly nanofabrication technologies. Here, we present a directional metasurface realized by breaking the out-of-plane symmetry of its individual elements: tilted subwavelength plasmonic gold nanopillars. Directionality is caused by the complex charge oscillation induced in each individual nanopillar, which essentially acts as a tilted dipole above a dielectric interface. The metasurface is homogeneous over a macroscopic area and it is fabricated by a combination of facile colloidal lithography and off-normal metal deposition. Fluorescence excitation and emission from dye molecules deposited on the metasurface is enhanced in specific directions determined by the tilt angle of the nanopillars. We envisage that these directional metasurfaces can be used as cost-effective substrates for surface-enhanced spectroscopies and a variety of nanophotonic applications.
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Verre
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Svedendahl
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Odebo Länk
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Yang
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Zengin
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.|Centre of New Technologies, University of Warsaw , Banacha 2c, 02-097 Warsaw, Poland.
authors.forename: T J
authors.initials: TJ
authors.lastname: Antosiewicz
authors.affiliation: Department of Applied Physics, Chalmers University of Technology , 412 96 Göteborg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Käll
keywords: Plasmonic antennas; cathodoluminescence; collodial mask lithography; directional emission; enhanced fluorescence; metamaterials