On the design of multi-vortex beam multiplexers using programmable metasurfaces

This paper presents an analytical procedure for designing orbital angular momentum (OAM) multiplexers with the capability of generating multiple multiplexed beams with different directions and OAM mode indices. The presented design method provides independent control of the power of each output OAM mode in a multiplexed beam. As a proof of concept, a metasurface with four incident beams and two multiplexed scattered beams with different directions and OAM modes is designed. It is based on a 2/2 bits phase–amplitude programmable metasurface which is numerically simulated, and the results are in good agreement with analytical predictions. The presented approach paves the way for design and implementation of multifunctional devices specially used in OAM communication systems.