Beam steering with nanoring reflectarray metasurfaces

One type of nanoring reflectarray metasurface is demonstrated to achieve high-efficiency beam steering in anomalous reflections. Rings with varied inner radius are designed to manipulate the phase front of the incident wave. The efficiency of anomalous reflections achieves more than 80% at the reflection angle of 53° under normal incidence. The light reflects along the surface of structure when the incident angle reaches to 12°. The anomalous reflection beams have the same polarization with the incoming light. This proposed structure can be applied in the high-efficiency waveplates, modulators, and couplers.