Fig. 1. Schematic of the light-controllable time-domain digital coding metasurface. Such a time-domain metasurface platform is constructed by integrating directly a high-speed photoelectric detection circuit into a full-polarization programmable metasurface. On this hybrid metasurface platform, the microwave reflection spectrum can be manipulated in real time by the light signal with different time-coding sequences.

Fig. 2. Reflection performance of the digital metasurface element. (a) Simulated reflection phase and amplitude curves of the element for two different capacitances CT under x- and y-polarized incidences. (b) Simulated reflection phase and amplitude curves of the element for two different capacitances CT under LCP and RCP incidences.

Fig. 3. The fabricated light-controllable time-domain digital coding metasurface and its performance. (a) Photograph of the programmable metasurface sample consisting of 18×18 digital metasurface elements. (b) Photograph of the high-speed photoelectric detection circuit integrated directly into the back of the metasurface sample. (c) Measured reflection phases of the light-controllable metasurface sample at several different frequencies for two different illumination intensities Ev under x-polarized and LCP incidences.

Fig. 4. Experiment setup and tested results. (a) Photograph of the experiment setup for spectrum tests. (b)–(e) Under x-polarized incidences, the measured reflected harmonics of the light-controllable time-domain metasurface at 6.5 GHz for two time-coding sequences of 0101010101… and 0010110111… with different modulation frequencies [(b), (c)] f0=100kHz and [(d), (e)] f0=200kHz. (f)–(i) Measured reflected harmonics for corresponding cases under LCP incidences.