A bifunctional reflector based on the chiral metasurface

Metasurfaces have attracted considerable attention due to their powerful abilities in electromagnetic wave manipulation and their easy fabrication. However, metasurface for circularly polarized waves with spin selective absorption characteristics has been less discussed. In this paper, an asymmetric chiral resonator lacking the mirror symmetry plane is studied, which presents different reflection properties for left-handed circularly polarized (LHCP) and right-handed circularly polarized (RHCP) waves. According to the theory of Pancharatnam-Berry (PB) phase, a bifunctional reflector based on the chiral unit is designed, which converts incident RHCP waves into vortex waves without changing handedness, while it absorbs incident LHCP waves. Full wave simulations are performed to validate the bifunctional performances of the metasurface. Such chiral metasurface paves the way to spin selective modulation of wavefronts, and present broad application prospects in the field of planar electromagnetic devices and communications.