title: Modal decomposition of surface--plasmon whispering gallery resonators.
abstract: We resolve the resonant whispering gallery modes of plasmonic subwavelength ring cavities defined by circular grooves patterned into a gold surface. An interesting interplay is observed between subwavelength confinement and guiding along the groove. Full spatial and spectroscopic information is directly obtained using cathodoluminescence, including details of the nanoscale intensity distribution (spatial resolution 11 +/- 8 nm). Excellent agreement between measurements and rigorous electromagnetic theory is obtained, thus allowing us to assess the symmetry, ordering, degree of confinement, and near-field enhancement of the modes with unprecedented detail.
authors: Center for Nanophotonics, FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 113, 1098 XG Amsterdam, The Netherlands. vesseur@amolf.nl
authors: Ernst Jan R
authors: EJ
authors: Vesseur
authors: F Javier
authors: FJ
authors: García de Abajo
authors: Albert
authors: A
authors: Polman
mesh_terms: D004574:Electromagnetic Fields; D006046:Gold / Q000737:chemistry*; D049449:Luminescence; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D010316:Particle Size; D013499:Surface Properties
chemical_list: D006046:Gold