Optical Field Enhancement in Nanoscale Slot Waveguides of Hyperbolic Metamaterials

TL;DR

This paper demonstrates that nanoscale slot waveguides made of hyperbolic metamaterials can significantly enhance optical fields, surpassing conventional waveguides, through mode confinement and tailored permittivity properties.

Contribution

It introduces a novel design of hyperbolic metamaterial slot waveguides and analyzes their optical field enhancement both numerically and analytically.

Findings

Electric field can be 25 times stronger than in silicon waveguides.

Field enhancement is due to ultrahigh refractive indices and mode confinement.

Verification with realistic multilayer structures confirms the effect.

Abstract

Nanoscale slot waveguides of hyperbolic metamaterials are proposed and demonstrated for achieving large optical field enhancement. The dependence of the enhanced electric field within the air slot on waveguide mode coupling and permittivity tensors of hyperbolic metamaterials is analyzed both numerically and analytically. Optical intensity in the metamaterial slot waveguide can be more than 25 times stronger than that in a conventional silicon slot waveguide, due to tight optical mode confinement enabled by the ultrahigh refractive indices supported in hyperbolic metamaterials. The electric field enhancement effects are also verified with the realistic metal-dielectric multilayer waveguide structure.