Near-Field Analysis of Bright and Dark Modes on Plasmonic Metasurfaces   Showing Extraordinary Suppressed Transmission
  Plasmonic metasurfaces are investigated that consist of a sub wavelength line pattern in an ultrathin (~ 10 nm) silver film, designed for extraordinarily suppressed transmission (EOST) in the visible spectral range. Measurements with a near-field scanning optical microscope (NSOM) demonstrate that far field irradiation creates resonant excitations of antenna like (bright) modes that are localized on the metal ridges. In contrast, bound (dark) surface plasmon polaritons (SPPs) launched from an NSOM tip propagate well across the metasurface, preferentially perpendicular to the grating lines. 
Sabine Dobmann and Arian Kriesch and Daniel Ploss and Ulf Peschel
physics.optics