Large-Modulation-Depth Polarization-Sensitive Plasmonic Toroidal Terahertz Metamaterial

摘要

In this letter, we propose a terahertz (THz) plasmonic metamaterial based on planar metamolecule arrays with strong polarization sensitivity and large-modulation-depth for potential switching applications. Using both numerical and experimental studies, we analyzed the spectral features of the plasmonic unit cells. Employing bimetallic resonators, we showed that the proposed metamolecules can be efficiently tailored to support strong toroidal dipole resonant mode across the THz spectrum with high quality factor. The photo-induced toroidal moment with ultrasharp linewidth is used to design a polarization sensitive structure. This approach is the first utilization of toroidal metamaterials for switching applications, possessing strong potential to be used for advanced integrated photonic devices.