Propagation dynamics of the circular Airy Gaussian vortex beams in the fractional nonlinear Schr\"odinger equation

TL;DR

This paper explores how circular Airy Gaussian vortex beams behave in a fractional nonlinear Schrödinger system, revealing effects like autofocusing, beam focusing size, and vortex dynamics influenced by fractional diffraction and nonlinear effects.

Contribution

It provides new insights into the propagation and autofocusing behavior of CAGVBs in fractional nonlinear media, including effects of fractional diffraction, distribution factor, power, and topological charge.

Findings

Autofocusing effect weakens with increased fractional diffraction Lévy index.

Focusing length becomes longer as distribution factor increases.

CAGVBs exhibit outward acceleration and autodefocusing properties.

Abstract

We have investigated the propagation dynamics of the circular Airy Gaussian vortex beams (CAGVBs) in a (2+1)-dimesional optical system discribed by fractional nonlinear Schr\"odinger equation (FNSE). By combining fractional diffraction with nonlinear effects, the abruptly autofocusing effect becomes weaker, the radius of the focusing beams becomes bigger and the autofocusing length will be shorter with increase of fractional diffraction L\'evy index. It has been found that the abruptly autofocusing effect becomes weaker and the abruptly autofocusing length becomes longer if distribution factor of CAGVBs increases for fixing the L\'evy index. The roles of the input power and the topological charge in determining the autofocusing properties are also discussed. Then, we have found the CAGVBs with outward acceleration and shown the autodefocusing properties. Finally, the off-axis CAGVBs with positive vortex pairs in the FNSE optical system have shown interesting features during propagation.