Co-axial superposition: generation of perfect vortex beams with multi-openings and adjustable spherical symmetry.

Abstract

The perfect vortex beam, with a diameter that remains independent of the topological charge, has numerous applications in far-field information propagation. In this study, a hologram is obtained through the co-spiral superposition of two primary spiral axicons which is assigned to spatial light modulator for the generation of perfect vortex beams. Key parameters such as the topological charge and intra-ring spacing of individual spiral axicons play critical roles in controlling the characteristics of the resulting perfect vortex beam through the resultant hologram. By adjusting these parameters, precise control can be exerted over the number of openings in the beam and the diameter of the central dark area of the beam. The generation of the entire family of vortex beams with both odd and even numbers of openings in both symmetrical and asymmetrical geometry of the vortex beam petals is presented in simulation and experiment. The perfect vortex beam reported here is characterized by its adjustable number of openings and controllable petal size, holding significant potential for applications in optical trapping. The existence of multiple circular vortex petals with different radii is expected to enable the optical sorting of different particles.