Three-dimensional simultaneous arbitrary-way orbital angular momentum generator for future communication applications

In this work, a three-dimensional (3D) simultaneous arbitrary-way orbital angular momentum (OAM) generator is presented. The proposed generator is constructed by a group of transformation cylinders filled with metamaterials. Using transformation cylinders, arbitrary-way planar wave fronts can be simultaneously converted to helical wave fronts with arbitrary topological charges. Firstly, the principle of orbital angular momentum is introduced. Then, a designing method of metamaterials based on transformation optics is interpreted to construct a 3D simultaneous arbitrary-way OAM generator with different topological charges. At last, the simulations on electric field and phase of output beams are performed, which validate the function of this design. The results show that arbitrary-way beams carrying OAM with specific topological charges can be obtained simultaneous by the proposed device.