Fig. 5
From: Multifunctional graphene metasurface to generate and steer vortex waves
Illustration of combining two metasurfaces into one multifunctional metasurface. In the inset, the electromagnetic waves are impinging normally from upper space with refractive index ni. a Metasruface 1 (MS1) with phase discontinuity ϕ1(x) and b metasurface 2 (MS2) with phase discontinuity ϕ2(x) are combined into c the desired multifunctional metasurface (MSt) with phase discontinuity ϕt(x). θr1(x), θr2(x) and θrt(x) are the angles of anomalous reflection along the interfaces of the metasurfaces, respectively, and the relationship θrt(x)=θr1(x)+θr2(x) holds everywhere in MSt