Reconfigurable Metagratings

Recently, it was revealed that gradient metasurfaces based on continuous gradients of the local reflection and/or transmission coefficients are fundamentally limited on their overall efficiency in transformation of an impinging wavefront. In addition, due to the fastly varying impedance profile that these surfaces require, they usually need high-resolution fabrication processes. To address these issues, the concept of metagrating was recently put forward, enabling engineered surfaces capable of manipulating light with unitary efficiency. Metagratings are periodic arrays of carefully designed scatterers that, in contrast with conventional metasurfaces, do not need to support a continuous gradient surface impedance, and consequently, are far simpler to fabricate. Building up on this concept, here we explore opportunities to realize reconfigurable multifunctional metagratings. The proposed designs provide a highly efficient reconfigurable platform tuned by electrostatically biasing simply structured graphene sheets, paving the way to a new generation of highly efficient designer surfaces.