Theory of extreme optical concentration in all-dielectric waveguides

TL;DR

This paper presents a new class of all-dielectric waveguides that achieve extreme sub-wavelength light confinement, enabling advanced nanophotonic devices without using metals or plasmonics.

Contribution

Introduction of transversely structured all-dielectric waveguides exploiting light's vectorial nature for ultra-confined modes and a new metric for optical concentration.

Findings

Achieved mode dimensions below λ₀²/1,000 without metals.

Derived a practical metric for optical concentration.

Enabled enhanced linear and nonlinear nanoscale interactions.

Abstract

We introduce transversely structured all-dielectric waveguides which exploit the vectorial nature of light to achieve extreme sub-wavelength confinement in high index dielectrics, enabling characteristic mode dimensions below $\lambda_0^2$/1,000 without metals or plasmonics. We also derive the metric of optical concentration and show its convenient usage in characterizing enhanced linear and non-linear interactions at the nanoscale. This work expands the toolbox of nanophotonics and opens the door to new types of ultra-efficient and record performing linear and nonlinear devices with broad applications spanning classical and quantum optics.