Time-varying metasurfaces for arbitrary parametric wave control

Huygens' metasurfaces allow almost arbitrary wave-front shaping. However, it remains highly nontrivial to achieve dynamic and arbitrary control of the amplitude and phase response. Here we show that in a system consisting of both electric and magnetic meta-atoms with independently controlled modulation, the incident wave can be efficiently converted to sidebands of new frequencies, whose scattering directionality, phase and conversion efficiency can be manipulated almost arbitrarily