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

Area of Science:

• Nonlinear optics
• Soliton physics
• Optical vortex dynamics

Background:

• Optical vortex solitons (VSs) are fundamental nonlinear light structures.
• Controlling the stability and properties of VSs is crucial for optical applications.
• Previous models often struggle to achieve stable high-topological-charge VSs.

Purpose of the Study:

• To propose a novel model for trapping stable optical vortex solitons (VSs) with high topological charges (m).
• To investigate the influence of refractive index modulation on VS stability.
• To identify conditions supporting stable, narrow, low-power VSs.

Main Methods:

• Development of a theoretical model for VSs in a cubic-quintic nonlinear medium.
• Imprinting a ring-shaped modulation of the refractive index.
• Analysis of VS stability using the anti-Vakhitov-Kolokolov criterion.
• Numerical simulations to validate theoretical predictions.

Main Results:

• The model supports two branches of VSs, controlled by modulation parameters (radius, width, depth).
• Lower-branch VSs are largely unstable, while the upper branch exhibits complete stability.
• VSs with topological charges m ≤ 12 satisfy the anti-Vakhitov-Kolokolov stability criterion.
• Stable narrow optical VSs with high vorticities and low power are achievable.

Conclusions:

• A stable trapping model for optical vortex solitons is demonstrated.
• Refractive index modulation is a key factor in achieving stable VSs.
• The findings pave the way for practical applications of stable, high-charge optical vortices.