Electrically-reconfigurable high quality factor metasurfaces for dynamic wavefront shaping

Apparatus comprising:

• an electromagnetic metasurface including two or more waveguides disposed on a surface;
• wherein each of the two or more waveguides supports one or more guided modes;
• wherein each of the two or more waveguides has a corresponding longitudinal perturbation, whereby at least one guided mode resonance is supported in each of the two or more waveguides;
• wherein free-space radiation is coupled to a selected two or more of the guided mode resonances by the longitudinal perturbations of the two or more waveguides;
• wherein the selected two or more of the guided mode resonances are tunable according to at least one tuning input, whereby a free-space response provided by the electromagnetic metasurface is tunable.