Design and validation of a metasurface lens for converging vortex beams

Abstract

In this letter, a phase-gradient metasurface (MS) lens whose elements satisfy high transmittance and desired transmission phase is proposed to achieve collimation of vortex beams generated by an orbital angular momentum (OAM) radiating source. Two different phase profiles, hyperbolic and conical, are calculated and simulated. In addition, a prototype based on the conical phase profile is fabricated and experimentally tested, which verifies that the MS lens can realize effective collimation functionality. The proposed integrated lens-antenna system is able to provide new possibilities for OAM applications in radio wireless communication, imaging, and sensing.