Rotating azimuthons in dissipative Kerr media excited by superpositions of Bessel beams

TL;DR

This paper demonstrates the existence of stable, rotating azimuthons in dissipative Kerr media, excited by superpositions of Bessel beams, which exhibit unique topological charge inversion and are relevant for high-intensity light filamentation.

Contribution

It introduces a new class of rotating azimuthons in dissipative Kerr media excited by Bessel beam superpositions, highlighting their stability, topological charge inversion, and experimental relevance.

Findings

Rotating azimuthons exist in dissipative Kerr media with self-focusing and absorption nonlinearities.

The azimuthons exhibit opposite vorticity in the center compared to the input superposition.

They can reproduce observed helical light filaments near ionization thresholds.

Abstract

We report the existence of persistently rotating azimuthons in media with self-focusing Kerr and absorption nonlinearities. The nonlinear loss is balanced by power influx from the peripheral reservoir stored in slowly decaying tails of the azimuthons. These modes are excited by a superposition of two Bessel beams with opposite vorticities, $\pm s$, and slightly different conicities. The excited azimuthon exhibits opposite vorticity in its center to that of the input Bessel-beam superposition due to spontaneous inversion of the topological charge in the course of the azimuthon formation. Unlike azimuthons in loss-free media, number $N$ of rotating intensity maxima and $s$ are not mutually independent, being related by $N=2s$. The robustness of the rotating azimuthons is enhanced in comparison to similar static dissipative patterns. They can be excited in almost any transparent material, in the range of intensities for which the nonlinear absorption, induced by multiphoton absorption, is relevant. Close to the ionization threshold, the rotating azimuthons reproduce recently observed helical filaments of light in air and CS$_{2}$.