Multi-region spiral photon sieve to produce tailorable multiple vortex

Herein, we propose a mull-region spiral photon sieve in which each region has its features like focus and topological charge. Because the segmentation offers us to consider each region as an individual spiral photon sieve to manage the focusing behavior of the element. Accordingly, we have considered a four-region element so any region has its main focus specified by the parameter a. As a result, it is demonstrated that depending on the number of zones in each region the element offers a multi-vortex generator so that the spacing between the vortices is tailorable. In the meantime, we have indicated that the generated vortices may have the same or different vorticity considering the topological charge of each region. Lastly, some corresponding experiments were arranged and carried out to verify the simulation predictions.