title: Nanoscale optical field localization by resonantly focused plasmons.
abstract: We experimentally demonstrate use of plasmonic resonant phenomena combined with strong field localization to enhance efficiency of confining optical fields in a Si waveguide. Our approach utilizes a plasmonic resonant nano-focusing-antenna (RNFA), that simultaneously supports several focusing mechanisms in a single nanostructure, integrated with a lossless Si waveguide utilized with silicon-on-insulator (SOI) technology, to achieve a sub-diffraction limited focusing with a nanoscale (deeply subwavelength) spot size. The metallic RNFA effectively converts an incoming propagating waveguide mode to a localized resonant plasmon mode in an ultrasmall volume in all 3 dimensions. The near-field optical measurements of the fabricated RNFA using heterodyne near-field scanning optical microscope (H-NSOM) validate the theoretical predictions showing strong optical field localization.
authors.affiliation: Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, CA 92093, USA. lifeng@ucsd.edu
authors.forename: Liang
authors.initials: L
authors.lastname: Feng
authors.forename: Derek
authors.initials: D
authors.lastname: Van Orden
authors.forename: Maxim
authors.initials: M
authors.lastname: Abashin
authors.forename: Qian-Jin
authors.initials: QJ
authors.lastname: Wang
authors.forename: Yan-Feng
authors.initials: YF
authors.lastname: Chen
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Lomakin
authors.forename: Yeshaiahu
authors.initials: Y
authors.lastname: Fainman