Light guiding above the light line in arrays of dielectric nanospheres

TL;DR

This paper demonstrates that arrays of dielectric nanospheres can support quasi-bound leaky modes that enable light to propagate over long distances near the bound states in the radiation continuum, combining numerical and semi-analytical methods.

Contribution

It introduces the concept of guiding light above the light line in dielectric nanosphere arrays and provides both numerical and semi-analytical analysis of these modes.

Findings

Leaky modes can propagate hundreds of wavelengths.

Propagation occurs near bound states in the radiation continuum.

Semi-analytical decay rate estimates match numerical results.

Abstract

We consider light propagation above the light line in arrays of spherical dielectric nanoparticles. It is demonstrated numerically that quasi-bound leaky modes of the array can propagate both stationary waves and light pulses to a distance of hundreds wavelengths at the frequencies close to the bound states in the radiation continuum. A semi-analytical estimate for decay rates of the guided waves is found to match the numerical data to a good accuracy.