Optically tunable scattering using epsilon-near-zero-enabled nonlinear nanoantennas

Optical nanoantennas provide extraordinary capabilities in controlling light at subwavelength scale. It attracts increasing interest that how to achieve tunable nanoantennas for flexible and multifunctional miniaturized optical applications. Here, a sandwich-type nonlinear nanoantenna with a thin layer of epsilon-near-zero (ENZ) material is proposed to dynamically tune the far-field scattering via an all-optical approach. By synthetically combining the varying dependence of four fundamental Mie modes on refractive index and giant intensity-dependent refractive index change caused by nonlinear optical effect in ENZ material, the far-field scattering of the proposed nonlinear nanoantenna can be dynamically tuned from bidirectional to transverse or unidirectional scattering by readily controlling the intensity of incident light. We believe that the proposed all-optical nonlinear optical nanoantennas will motivate more promising applications of all-optical light modulation for photonic devices.