Reconfigurable Vector Vortex Beams Using Spoof Surface Plasmon Ring Resonators

In this article, a spoof surface plasmon (SSP) ring resonator to generate dynamically reconfigurable vortex beams is proposed. According to the phase constant control of the SSP and the harmonic radiation principle, the tunable cylindrical vector vortex beams (VVBs) with different topological charges can be obtained. The tunable system that operates by electronic control would utilize varactors to change the wavenumber of SPP on the ring resonator and realize the reconfigurable VVBs modes at a fixed frequency. All VVBs have excellent orbital angular momentum (OAM) purity (above 90%). Interestingly, the antenna also simultaneously radiates the scalar vortex beams with tunable OAM modes. Both numerical simulations and experimental characterizations confirm the theoretical predictions. Because the designed antenna has the advantages of simple feeding network, easy bias circuit, as well as miniaturization and integration compatibility, we anticipate that the antenna will enable a wide range of applications for future wireless communication and imaging technologies.