Liquid crystal integrated metamaterial for multi-band terahertz linear polarization conversion
Shi‐Tong Xu, Fei Fan, Hong-Zhong Cao, Ying‐Hua Wang, Shengjiang Chang
Abstract
We experimentally investigate the linear polarization conversion for terahertz (THz) waves in liquid crystal (LC) integrated metamaterials, which consist of an LC layer sandwiched by two orthogonally arranged sub-wavelength metal gratings. A Fabry-Perot-like cavity is well constructed by the front and rear gratings, and it shows a strong local resonance mechanism, which greatly enhances the polarization conversion efficiency. Most importantly, the Fabry-Perot-like resonance can be actively tuned by modulating the refractive index of the middle LC layer under the external field. As a result, the integrated metamaterial achieves multi-band tunable linear polarization conversion.