Light-Controllable Digital Coding Metasurfaces.

Since the advent of digital coding metamaterials, a new paradigm is unfolded to sample, compute and program electromagnetic waves in real time with one physical configuration. However, one inconvenient truth is that actively tunable building blocks such as diodes, varactors, and biased lines must be individually controlled by a computer-assisted field programmable gate array and physically connected by electrical wires to the power suppliers. This issue becomes more formidable when more elements are needed for more advanced and multitasked metadevices and metasystems. Here, a remote-mode metasurface is proposed and realized that is addressed and tuned by illuminating light. By tuning the intensity of light-emitting diode light, a digital coding metasurface composed of such light-addressable elements enables dynamically reconfigurable radiation beams in a control-circuitry-free way. Experimental demonstration is validated at microwave frequencies. The proposed dynamical remote-tuning metasurface paves a way for constructing unprecedented digital metasurfaces in a noncontact remote fashion.