Quasi-non-diffraction circular Pearcey vortex beam generation through a transmission metasurface

Quasi-non-diffraction beam plays an important role in suppressing the divergence angle of the vortex electromagnetic wave. In this paper, a circular Pearcey beam is applied for orbital angular momentum (OAM) vortex beam’s divergence angle suppression, and a quasi-non-diffraction circular Pearcey vortex beam is generated with a transmission metasurface in the millimeter wave band. A full design method of the quasi-non-diffraction circular Pearcey vortex beam is proposed, and it is discussed in detail. An amplitude and phase controllable transmission metasurface working at 30 GHz is designed to generate a quasi-non-diffraction circular Pearcey (QCP) vortex beam with OAM mode of l = + 1. The simulated circular Pearcey vortex beam exhibits a distinct quasi-non-diffraction characteristic. Moreover, the circular Airy vortex beam and the conventional OAM vortex beam are also simulated and analyzed to compare with the designed Pearcey vortex beam. To further validate the proposed method, the designed transmission metasurface is fabricated and measured, and the measurement results align well with the simulation.