Stabilization of Axisymmetric Airy Beams by Means of Diffraction and Nonlinearity Management in Two-Dimensional Fractional Nonlinear Schr\"{o}dinger Equations

Abstract

The propagation dynamics of two-dimensional (2D) ring-Airy beams is studied in the framework of the fractional Schr\"{o}dinger equation, which includes saturable or cubic self-focusing or defocusing nonlinearity and L\'{e}vy index ((LI) alias for the fractionality) taking values $1\leq\alpha \leq 2$. The model applies to light propagation in a chain of optical cavities emulating fractional diffraction. Management is included by making the diffraction and/or nonlinearity coefficients periodic functions of the propagation distance, $\zeta$. The management format with the nonlinearity coefficient decaying as $1/\zeta$ is considered, too. These management schemes maintain stable propagation of the ring-Airy beams, which maintain their axial symmetry, in contrast to the symmetry-breaking splitting instability of ring-shaped patterns in 2D Kerr media. The instability driven by supercritical collapse at all values $\alpha < 2$ in the presence of the self-focusing cubic term is eliminated, too, by the means of management.