Metagratings: Beyond the Limits of Graded Metasurfaces for Wave Front Control

Graded metasurfaces exploit the local momentum imparted by an impedance gradient to transform the impinging wavefront. This approach suffers from fundamental limits on the overall conversion efficiency and it is challenged by fabrication limitations on the maximum spatial resolution. Here, we introduce the concept of meta-gratings, which enables arbitrary wavefront engineering with unitary efficiency and significantly lower demands on the fabrication precision. We employ this concept to design reflective metasurfaces for wavefront steering without limitations on efficiency. A similar approach is envisioned for transmitted beams and for arbitrary wavefront transformation, opening promising opportunities for…

• NS
  National Science Foundation
• SF
  Simons Foundation
• WF
  Welch Foundation

  Award: F-1802
• AF
  Air Force Office of Scientific Research

  Award: FA9550-17-1-0002