# Possibility of negative refraction for visible light in disordered all-dielectric resonant high index metasurfaces

## TL;DR

This study demonstrates that disordered all-dielectric metasurfaces made of gallium phosphide spheres can exhibit negative refraction at visible wavelengths, depending on nanoparticle concentration and size, using FDTD simulations.

## Contribution

It provides the first evidence that disordered high-index dielectric metasurfaces can achieve negative refraction at visible light wavelengths.

## Key findings

- Negative refraction observed in disordered GaP metasurfaces.
- Effective refractive index depends on nanoparticle size and concentration.
- Negative refraction occurs only in a monolayer configuration.

## Abstract

Effective refractive index of disordered all-dielectric metasurfaces consisting of gallium phosphide (GaP) spheres is studied by means of three-dimensional finite-difference time-domain (FDTD) simulations at the wavelength of 532~nm. It is shown that a mixture of the high index nanoparticles with sizes close to the first magnetic and electric resonances randomly dispersed on metasurface may possess negative refraction. The dependence of the metasurface effective refractive index on the nanoparticle concentration and size is constructed. The feasibility of negative refraction at large concentrations of the high index resonant spheres is demonstrated. The negative effective refractive index is exhibited only for a monolayer of GaP spheres.