Nanoscale Metamaterial Optical Waveguides with Ultrahigh Refractive Indices

TL;DR

This paper introduces deep-subwavelength optical waveguides using metal-dielectric multilayer indefinite metamaterials, achieving ultrahigh refractive indices and small mode areas, enabling advanced light-matter interaction applications.

Contribution

It presents a novel design of nanoscale metamaterial waveguides with ultrahigh refractive indices and analyzes their modes and cutoff mechanisms through simulations.

Findings

Achieved ultrahigh effective refractive index of 62.0 at telecom wavelengths.

Realized waveguides smaller than λ0/50 with mode areas around 10^-4 λ0^2.

Demonstrated deep-subwavelength confinement and mode control in metamaterial waveguides.

Abstract

We propose deep-subwavelength optical waveguides based on metal-dielectric multilayer indefinite metamaterials with ultrahigh effective refractive indices. Waveguide modes with different mode orders are systematically analyzed with numerical simulations based on both metal-dielectric multilayer structures and the effective medium approach. The dependences of waveguide mode indices, propagation lengths and mode areas on different mode orders, free space wavelengths and sizes of waveguide cross sections are studied. Furthermore, waveguide modes are also illustrated with iso-frequency contours in the wave vector space in order to investigate the mechanism of waveguide mode cutoff for high order modes. The deep-subwavelength optical waveguide with a size smaller than {\lambda}0/50 and a mode area in the order of 10-4 {\lambda}02 is realized, and an ultrahigh effective refractive index up to 62.0 is achieved at the telecommunication wavelength. This new type of metamaterial optical waveguide opens up opportunities for various applications in enhanced light-matter interactions.