Characterization of the Propagation Dynamics of the Topological Charge Pairs Embedded in Auto-Focusing Airy Vortex Beam

Topological charge splitting leads to information sending and receiving mismatch in orbital angular momentum communication systems. In this paper, the topological charge splitting evolution law of auto-focusing Airy vortex beams carrying different vortex pairs is investigated during the transmission process. It is found that the split all-simultaneous topological charge has the repulsion phenomenon similar to that of like electric charges in the cross section of the optical field, and the topological charge splitting motion is the result of the combined action of the auto-focusing effect and the repulsion effect. This study provides an important reference for the transmission evolution of vortex beams in free space and the communication technology based on orbital angular momentum.