High-Efficiency Transmission-Type Digital Coding Metasurface for Metalens and Transmitarray

We introduce an elaborate design of 3-bit high-efficiency transmission-type digital coding metasurface, which is used to achieve excellent transmitarray and metalens. All eight meta-particles have good transmittance larger than 95% and keep 45° phase difference between every two adjacent states, and hence can be used as the digital codes of the 3-bit coding metasurface. The designed sample by the particles can focus the plane waves or convert the spherical waves to plane waves efficiently, which can be regarded as metalens and transmitarray, respectively. The simulated results show very good performance and agree well with the theoretical analysis.