Diffractive analysis of spiral checkerboard zone plate

Abstract

This work studies the unique behavior of spiral checkerboard zone plates under plane wave illumination. The element is constructed by superimposing two orthogonal helical linear zone plates. Based on their topological charge, various structured beams are generated whose structures display fascinating dynamics. Structure transforming, vortex pair production, annihilation, and the interaction of dipole and singular vortices, are some of the observed phenomena during the beam propagation produced by the element. On top of all that, we see the interaction of screw dislocations in the way that they get closer together when the diffracted beam propagates toward the focus, and they move away from each other as the beam moves away from the focus.