title: Superfocusing of electric or magnetic fields using conical metal tips: effect of mode symmetry on the plasmon excitation method.
abstract: We compare single- and double-sided excitation methods of adiabatic surface plasmon polariton (SPP) wave superfocusing for scattering-type metallic near-field scanning optical microscopy (s-NSOM). Using the results of full 3D finite difference time domain analyses, the differences in field enhancement factors are explained and reveal the mode selectivity of a conical NSOM tip for adiabatic SPP superfocusing. Exploiting the mode-symmetric nature of the tip further, we also show that it is possible to selectively confine either the electric or magnetic field at the NSOM tip apex, by simply adjusting the relative phase between the SPP waves in the double-sided excitation approach.
authors.affiliation: Photonic Systems Laboratory, EECS, Seoul National Univ., Seoul, 151-742 Korea.
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Lee
authors.forename: Sanghoon
authors.initials: S
authors.lastname: Han
authors.forename: Javid
authors.initials: J
authors.lastname: Shirdel
authors.forename: Sukmo
authors.initials: S
authors.lastname: Koo
authors.forename: Diyar
authors.initials: D
authors.lastname: Sadiq
authors.forename: Christoph
authors.initials: C
authors.lastname: Lienau
authors.forename: Namkyoo
authors.initials: N
authors.lastname: Park
mesh_terms: D004574:Electromagnetic Fields; D020342:Finite Element Analysis; D007368:Interferometry / Q000295:instrumentation / Q000379:methods; D008670:Metals / Q000737:chemistry*; D008853:Microscopy / Q000295:instrumentation / Q000379:methods*; D049329:Nanostructures; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000295:instrumentation / Q000379:methods*
chemical_list: D008670:Metals