Stable higher-charge vortex solitons in the cubic-quintic medium with a ring potential

TL;DR

This paper demonstrates a model for stabilizing high-charge optical vortex solitons in a cubic-quintic medium with a ring potential, revealing stable solutions for charges up to 12, which could enable low-power, high-vorticity optical applications.

Contribution

The study introduces a new approach to stabilize high-charge vortex solitons using a ring-shaped refractive index modulation in a cubic-quintic nonlinear medium.

Findings

Upper branch vortex solitons are fully stable.

Vortex charges up to 12 obey the anti-Vakhitov-Kolokolov criterion.

Stable, low-power high-vorticity optical solitons are possible.

Abstract

We put forward a model for trapping stable optical vortex solitons (VSs) with high topological charges $m$. The cubic-quintic nonlinear medium with an imprinted ring-shaped modulation of the refractive index is shown to support two branches of VSs, which are controlled by the radius, width and depth of the modulation profile. While the lower-branch VSs are unstable in their nearly whole existence domain, the upper branch is completely stable. Vortex solitons with $m\leq 12$ obey the anti-Vakhitov-Kolokolov stability criterion. The results suggest possibilities for the creation of stable narrow optical VSs with a low power, carrying higher vorticities.