Dynamics of topological light states in spiraling structures

TL;DR

This paper demonstrates how spiraling guiding structures can dynamically generate and control topological light states, such as optical vortices, through resonant coupling influenced by nonlinearity and guiding geometry.

Contribution

It introduces a mechanism for controlling topological light states in spiraling structures, including vortex excitation and topological charge manipulation, with applications in various guiding geometries.

Findings

Resonant coupling enables vortex generation from vortex-free inputs.

Nonlinearity causes asymmetrization and frequency shifts in resonances.

Topological light states can be controlled in both waveguides and hollow-core geometries.

Abstract

We expose a mechanism for the dynamical generation and control of light states with diverse topologies in spiraling guiding structures. Specifically, we show that spiraling shallow refractive index landscapes induce coupling and periodic energy exchange between states with different topological charges. Such a resonant effect enables excitation of optical vortices by vortex-free inputs and allows the output topological charge of the beam to be controlled. The presence of nonlinearity results in a strong asymmetrization of the resonant curves and a shift of the resonant frequencies. Resonant vortex dynamic generation, including revivals, is shown to be possible not only in waveguides mediated by total internal reflection but also in Bragg-guiding hollow-core geometries.