Trifunctional metasurfaces: concept and characterizations.

Achieving multiple diversified functionalities in a single flat device is crucial for electromagnetic (EM) integration. While many recent efforts were devoted to designing multifunctional metasurfaces, most meta-devices realized so far typically exhibit only two functionalities. In this paper, we propose a generic strategy to design trifunctional metasurfaces, based on carefully designed single structure meta-atoms possessing polarization-controlled transmission/reflection properties. As a proof of our concept, we design and fabricate a trifunctional metasurface possessing simultaneously three distinct functionalities including beam splitting, deflecting, and focusing, and perform both far-field and near-field microwave experiments to demonstrate the predicted functionalities of the fabricated device. Experimental results are in good agreement with numerical simulations. These findings can motivate the realizations of high-performance multifunctional meta-devices in different frequency domains and with diversified functionalities.