Dielectric Mie Voids: Confining Light in Air

TL;DR

This paper introduces a novel dielectric nanophotonics approach using air-filled Mie voids in silicon to achieve resonant light confinement down to UV wavelengths, enabling advanced optical device design.

Contribution

Demonstrates the experimental realization of resonant air-filled Mie voids in silicon for nanoscale light confinement, expanding the design space for metasurfaces and UV optical components.

Findings

Resonant modes supported by air voids in high-index dielectrics.

Achieved light confinement at 265 nm UV wavelength.

Enabled nanoscale colour printing with naturalistic colours.

Abstract

Manipulating light on the nanoscale has become a central challenge in metadevices, resonant surfaces, nanoscale optical sensors, and many more, and it is largely based on resonant light confinement in dispersive and lossy metals and dielectrics. Here, we experimentally implement a novel strategy for dielectric nanophotonics: Resonant subwavelength confinement of light in air. We demonstrate that voids created in high-index dielectric host materials support localized resonant modes with exceptional optical properties. Due to the confinement in air, the modes do not suffer from the loss and dispersion of the dielectric host medium. We experimentally realize these resonant Mie voids by focused ion beam milling into bulk silicon wafers and experimentally demonstrate resonant light confinement down to the UV spectral range at 265 nm (4.68 eV). Furthermore, we utilize the bright, intense, and naturalistic colours for nanoscale colour printing. The combination of resonant dielectric Mie voids with dielectric nanoparticles will more than double the parameter space for the future design of metasurfaces and other micro- and nanoscale optical elements and push their operation into the blue and UV spectral range. In particular, this extension will enable novel antenna and structure designs which benefit from the full access to the modal field inside the void as well as the nearly free choice of the high-index material.