Transformation of OAM waves to Plane Spiral OAM waves Based on Gradient-index Meta-surface

The conventional Orbital Angular Momentum (OAM) waves, which propagate along the main axis are transformed into the plane spiral OAM' waves based on Gradient index Meta-surface. The cell of the meta-surface contains three layers with a metallic 'H', a dielectric spacer and a metal plate. Using the radial arrangement of the metallic 'H' cells, the conventional OAM waves can be transformed into the plane spiral OAM waves when they normally illuminate on the meta surface. Thus, multiple OAM beams can be converted into the corresponding PSOAM beams using the same meta-surface and be superposed to realize the structured EM waves.