Optically controlled beam steering in nonlinear all-dielectric metasurfaces

We demonstrate optically tunable control of second-harmonic generation in all dielectric nano-antennas: by using a control beam which is absorbed by the nano-resonator, we thermo-optically change the refractive index of the radiating element to modulate amplitude and phase of the second-harmonic signal. For a moderate temperature increase, sizeable modulation is demonstrated; the large tunability of the single meta-atom response paves the way to exciting avenues for reconfigurable homogeneous and heterogeneous metasurfaces.