Metamirrors
  We introduce the concept of non-uniform metamirrors (full-reflection metasurfaces) providing full control of reflected wave fronts independently from the two sides of the mirror. Metamirror is a single planar array of electrically small bianisotropic inclusions. The electric and magnetic responses of the inclusions enable creating controlled gradient of phase discontinuities over the surface. Furthermore, presence of electromagnetic coupling in the inclusions allows independent control of reflection phase from the opposite sides of the mirror. Based on the proposed concept, we design and simulate metamirrors for highly efficient light bending and near-diffraction-limit focusing with a sub-wavelength focal distance. 
Viktar Asadchy, Younes Radi, and Sergei Tretyakov
physics.optics