Metagratings for Efficient Wavefront Manipulation

Metagratings are two-dimensional periodic arrays of individual scatterers that enable highly-efficient extreme wave transformation which was impossible using conventional metasurfaces. We review our recent progress in this area and, notably, discuss metagrating designs based on asymmetric electric dipoles that are practically easier to realize compared to bianisotropic inclusions. In addition, we present the design of a tunable metagrating based on graphene strips. It will be shown that the proposed structure can provide multiple functionalities by tuning just two bias voltages. The efficiency of the proposed design is only limited by dissipation in graphene.