Nonlinear Optical Responses in Metamaterials

Metamaterials hold unique characteristics including anisotropy, chirality, and coupling of multi-physical degrees of freedom. However, the research on the nonlinear optical response of metamaterials in the terahertz (THz) region is still in its early stages until now, and the physical mechanisms of THz generation from metamaterials are interesting yet complex. As such, it is pivotal to effectively generate and control the nonlinear optical response of metamaterials, as well as exploiting metamaterials into THz science and technology. Herein, we have designed a metamaterial consisting of metallic resonator arrays and all-dielectric silicon split rings (SSRs), at which the interlayer coupling can significantly improve the THz generation. Interestingly, the THz generation can be modulated by the interlayer coupling intrinsically through tuning the orientation of the all-dielectric SSRs as well as extrinsically through tuning the incident polarization angle. This work paves a new way for the compact and tunable THz emitters and modulators.