Comprehensive focusing analysis of bi-segment spiral zone plate in producing a variety of structured light beams

This study introduces and demonstrates the diffractive feature of a bi-segment spiral zone plate, so that each segment has its own width, topological charge, and radial phase shift. We show that the focusing behavior of this element depends strongly on these parameters. We demonstrate how these features can handle the focused intensity and structure of an incident plane beam. A variety of beam shapes and structures are generated at the focal plane. Theoretical and simulation results are verified by the corresponding experiments.