1-bit digital orbital angular momentum vortex beam generator based on a coding reflective metasurface

In this paper, a 1-bit digital orbital angular momentum (OAM) vortex beam generator based on a coding reflective metasurface is proposed. Theoretical analyses are performed to demonstrate that the 1-bit digital metasurface with only 0 and pi Rreflection phase response elements can generate different OAM vortex beams flexibly. The compensation phase distribution calculation formula and phase fuzzification method are concluded. To validate this concept, a 1-bit 12 x 12 digital OAM generator that is mounted with PIN diodes and driven by microcontroller unit is designed and measured in the radio frequency domain. The experiment of the prototype reveals that the 1-bit digital OAM generator is an efficient way to generate vortex beams. Also, this concept breaks through the constraint of phase continuity of elements when generating OAM beams using reflective metasurfaces. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement