Metamaterials are artificial optical media composed of subwavelength metallic and
dielectric building blocks that feature optical phenomena not present in naturally occurring materials. Although they can serve as the basis for unique optical devices that mold the flow of light in unconventional ways, three-dimensional metamaterials suffer from extreme propagation losses. Two dimensional metamaterials
(metasurfaces) such as hyperbolic metasurfaces for propagating surface plasmon polaritons have the potential to alleviate this problem. Because the surface plasmon polaritons are guided at a metal–dielectric interface (rather than passing through metallic components), these hyperbolic metasurfaces have been predicted to suffer
much lower propagation loss while still exhibiting optical phenomena akin to those in
three dimensional metamaterials. Moreover, because of their planar nature, these
devices enable the construction of integrated metamaterial circuits as well as easy
coupling with other optoelectronic elements. In this presentation, I will introduce these
metamaterials and show you some peculiar properties of it.

Reference: A. A. High et al., Nature 522: 192, 193, 194, 195, 196 (2015). doi:10.1038/nature14477