title: Edge scattering of surface plasmons excited by scanning tunneling microscopy.
abstract: The scattering of electrically excited surface plasmon polaritons (SPPs) into photons at the edges of gold metal stripes is investigated. The SPPs are locally generated by the inelastic tunneling current of a scanning tunneling microscope (STM). The majority of the collected light arising from the scattering of SPPs at the stripe edges is emitted in the forward direction and is collected at large angle (close to the air-glass critical angle, θ(c)). A much weaker isotropic component of the scattered light gives rise to an interference pattern in the Fourier plane images, demonstrating that plasmons may be scattered coherently. An analysis of the interference pattern as a function of excitation position on the stripe is used to determine a value of 1.42 ± 0.18 for the relative plasmon wave vector (kSPP/k0) of the corresponding SPPs. From these results, we interpret the directional, large angle (θ~θ(c)) scattering to be mainly from plasmons on the air-gold interface, and the diffuse scattering forming interference fringes to be dominantly from plasmons on the gold-substrate interface.
authors.affiliation: Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS Université Paris-Sud, Orsay, France.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Boer-Duchemin
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.forename: Benoit
authors.initials: B
authors.lastname: Rogez
authors.forename: Geneviève
authors.initials: G
authors.lastname: Comtet
authors.forename: Eric
authors.initials: E
authors.lastname: Le Moal
authors.forename: Gérald
authors.initials: G
authors.lastname: Dujardin
authors.forename: Andreas
authors.initials: A
authors.lastname: Hohenau
authors.forename: Christian
authors.initials: C
authors.lastname: Gruber
authors.forename: Joachim R
authors.initials: JR
authors.lastname: Krenn
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry* / Q000528:radiation effects*; D008027:Light; D016252:Microscopy, Scanning Tunneling / Q000379:methods*; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods*
chemical_list: D006046:Gold