Recent advances on optical metasurfaces

Metasurfaces, the two-dimensional equivalent of metamaterials, are periodic arrays of sub-wavelength engineered inclusions that can locally manipulate and enhance wave-matter interactions, thus providing unprecedented possibilities to realize exotic wave phenomena over a sub-wavelength thickness. In this review, we summarize recent advances in the theoretical modeling, realization and application of optical metasurfaces, outlining their impact on integrated and free-space flatland nanophotonic components. We describe recent developments on the homogenization of periodic metasurfaces with arbitrary inclusion shape and geometry and, on the basis of this description, we revisit recent developments in this area of research, especially focusing on their optical applications for radiation control, lensing, beam shaping and optical communications.