Multi-focusing of a Ring Pearcey–Gaussian Beam Induced by Periodic Nonlinear Defocusing Nonlocality

In this paper, we investigate the dynamics of the inward-focusing ring Pearcey–Gaussian beam (IRPB) propagated in a type of defocusing nonlinear media with periodic-oscillatory nonlocality. An interesting phenomenon is found that the IRPB exhibits a multi-focusing property during propagation, which can be attributed to the periodic evolution of the defocusing nonlocality. Further, it is shown that the multi-focusing behavior can be controlled by adjusting the initial field parameters (the radius and amplitude of the beam). Such finding will provide a theoretical basis for the generation and regulation of multi-focusing beams in nonlinear regime, which may benefit for optical tweezers and particle manipulation.