title: Plasmonic focusing with a coaxial structure illuminated by radially polarized light.
abstract: We propose and analyze a plasmonic lens that is illuminated by a radially polarized light. The lens is made of a coax-like geometry consisting of an annular dielectric slit surrounded by metal. Focusing efficiency is enhanced by the use of a circular grating assisting the coupling of light into surface plasmons. Further enhancement is obtained by introducing a circular Bragg grating on top of the structure, reflecting the surface plasmon modes that are propagating in the counter-focus direction. Using the Finite-Difference Time-Domain approach we investigate the transmission and the focusing mechanisms, and study the effect of structural parameters on the performance of the plasmonic lens.
authors.affiliation: Department of Applied Physics, The Benin School of Engineering and Computer Science, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
authors.forename: Avner
authors.initials: A
authors.lastname: Yanai
authors.forename: Uriel
authors.initials: U
authors.lastname: Levy