Terahertz grafted perfect vortex beams with controllable grafted topological charges

We demonstrate what we believe to be a novel terahertz (THz) grafted perfect vortex beam (PVB), in which the grafted topological charges (TCs) can be arbitrarily combined as integers or fractions, and the grafted proportion of TCs can also be independently controlled. Pure-phase holograms of the THz grafted PVBs are generated using a modified dual-constraint Gerchberg-Saxton algorithm. The phase hologram plates are fabricated via 3D-printing for experimental validation. Simulated and experimental results show that the ring radius, grafted TCs, grafted proportion, and gap position of the THz grafted PVBs can be controlled by adjusting design parameters. These results increase the diversity of orbital angular momentum distributions in PVBs, thereby offering additional degrees of freedom for multidimensional light-field engineering.