Beam focusing using two-dimensional graphene-based meta-reflect-array

A highly efficient two-dimensional meta-reflect-array manipulating the phase and amplitude of far-infrared electromagnetic wave is proposed. The reflect array consists of patterned graphene nano-disks resides on a subwavelenght thick optical cavity to enhance the interaction of electromagnetic wave. It is shown that the reflected wave from each unit cell can almost cover the 2π range phase shift by changing the radius of the graphene nano-disks while at the same time maximizes its amplitude. Proposing a transmission line model for the proposed structure, we realize a meta lens as a flat optics functionality.