Plasmon resonant cavities in vertical nanowire arrays

摘要

Tunable plasmon resonant cavity arrays in paired parallel nanowire waveguides are presented. Resonances can be observed when the waveguide length is an odd multiple of quarter plasmon wavelengths, consistent with boundary conditions of node and antinode at the ends. Two nanowire waveguides can satisfy the dispersion relation of a planar metal-dielectric-metal waveguide of equivalent width equal to the square field average weighted gap. Confinement factors of over 103 are possible due to plasmon focusing in the inter-wire space.

主权项

1. A plasmonic structure comprising:
a planar substrate; and an array of metal-coated dielectric cylindrical nanowires, the cylindrical nanowires being aligned along two mutually perpendicular directions and being end-connected substantially orthogonally to the planar substrate so that plasmon resonant gap-cavities capable of supporting propagation of gap plasmon modes are formed between adjacent pairs of said nanowires with one end of each of said plasmon resonant gap-cavities delimited by a surface of the planar substrate and another end of each of said plasmon resonant gap-cavities open ended, wherein the cavities are capable of supporting gap plasmon modes excited by light normally incident on an open end side of the cavities.