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

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 ≤  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.