Figure 1.

Schematic illustrations of (a) a metasurface with gradually varying scatterers, and (b) a periodic metasurface. (c) Cross section view of the periodic metasurface shown in (b). A normally incident plane wave is impinging on the metasurface. The transmitted and reflected plane waves, and the polarization converted plane waves are also shown. (d) Illustration of the equivalent volume current density that has replaced the periodic metasurface. E_i, E_r0, and E_t0 are the electric fields of the incident, reflected and transmitted plane waves for a bare interface, respectively. The electric field of the light scattered by the metasurface is labeled by E_s|| for the part with the same polarization as E_r0 and E_t0, and by E_s⊥ for the part with polarization orthogonal to the polarizations of E_r0 and E_t0.