  In this paper, we theoretically and experimentally demonstrated
photothermally-induced nonlinearities of both forward and backward scattering
intensities from quasi-perfect absorbing silicon-based metasurface. The
metasurface is efficiently heated up by photothermal effect under laser
irradiation, which in turn modulates the scattering spectra via thermo-optical
effect. Under a few milliwatt continuous-wave excitation, backward scattering
cross-section doubles, and forward scattering cross-section reduces to half.
Our study opens up the all-optical dynamical control of the scattering
directionality, which would be applicable to silicon photonic devices.
