Generation of terahertz generalized perfect vortex beams in various spatial modes

A flexible approach for terahertz (THz) generalized perfect vortex beams (GPVBs) is proposed and experimentally showcased in various spatial modes. By the predefined curved trajectories and topological charges, we construct the amplitude and phase profiles of THz GPVBs to induce corresponding pure phase holograms computed by a modified dual-constraint Gerchberg-Saxton algorithm. In experiments, we fabricate the phase hologram plates to realize the THz GPVBs in single, multiplexed, coaxial, and arrayed curve modes, and the result indicates that the geometrical characteristics and carried topological charges of the THz GPVBs can be flexibly manipulated and customized. These THz GPVBs exhibit significant potential for encoding information in high-capacity THz mode-division multiplexing communications.