All‐optical scattering control in an all‐dielectric quasi‐perfect absorbing Huygens’ metasurface
Kentaro Nishida, Koki Sasai, Rongyang Xu, Te-Hsin Yen, Yu‐Lung Tang, Junichi Takahara, Shi‐Wei Chu
Abstract
Abstract In this paper, we theoretically and experimentally demonstrated photothermal nonlinearities of both forward and backward scattering intensities from quasi‐perfect absorbing silicon‐based metasurface with only λ /7 thickness. 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 at the resonance wavelength of the metasurface, 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.