Surface plasmon polaritons on metal cylinders with dielectric core - art. no. 125420

Metal-cladded dielectric cylinders with submicron diameters may serve to mo del coated tips used in nearfield scanning optical microscopy. The signal m easured may be greatly influenced by resonance effects due to eigenmodes of the probe. Especially, using a photon scanning tunneling microscope setup, gold-coated tips have been found to detect a signal proportional to the ma gnetic field distributions [E. Devaux et al.. Phys. Rev. B 62, 10 504 (2000 )]. This effect is attributed to cylindrical surface plasmons. We present h ere fully retarded calculations of the dispersion and field patterns of the nonradiative plasmon modes in cylindrical geometry. We study the effect of varying the cylinder radius on the surface plasmon dispersion, thus justif ying that the cylinder is a useful model for near-field probes in spite of their slightly conical shape.