Plasmon waveguide for optical far/near-field conversion

Abstract

A plasmon waveguide was designed and fabricated using a metal-coated silicon wedge structure that converts propagating far-field light to the near field. Illumination (λ=830 nm) of the waveguide (plateau width 150 nm) caused transverse magnetic plasmon-mode excitation. Use of a near-field microscope allowed us to determine its beam width and propagation length as 150 nm and 2.5 μm, respectively.