Metasurfaces for high index effective media

In this work we present different planar metasurfaces, comprised of two or more layers. These layers are stacked, with a very small separation, and displaced with respect to each other. By a correct choice of parameters, a high mode index is achieved. In addition, the way in which the metasurfaces are designed, comprised of independent patches, allow for the tailoring of the mode index across the metasurface.