Controlled interaction of the optical vortices generated by off-center spiral zone plates

We report a simple, cost-effective, and scalable diffractive optical element named off-center spiral zone plates (OSZPs) to generate composite optical vortices (OVs) and control their interactions. By adjusting the parameters of OSZPs, the interaction process and performance of OVs, including fluid-like rotation, annihilation of vortex anti-twins, and creation or destruction of vortex anti-twins are investigated. Besides, the rotation between the two vortices with opposite TCs is observed. Furthermore, it is revealed that the common OVs interaction is based on the process of creation and destruction of vortex anti-twins, which helps us to understand the dynamics of the underlying interactions of composite OVs.