Terahertz Chiral Metamaterials Enabled by Textile Manufacturing.

Easy-to-fabricate, large-area, and inexpensive microstructures that realize control of the polarization of terahertz (THz) radiation are of fundamental importance to the development of the field of THz wave photonics. However, due to the lack of natural materials that can facilitate strong THz radiation-matter interactions, THz polarization components remain an undeveloped technology. Strong resonance-based responses offered by THz metamaterials have led to the recent development of THz metadevices, whereas, for polarization control devices, micrometer-scale fabrication techniques including aligned photolithography are generally required to create multilayer microstructures. In this work, leveraging a two-step textile manufacturing approach, a chiral metamaterial capable of exhibiting strong chiroptical responses at THz frequencies is demonstrated. Chiral-selective transmission and pronounced optical activity are experimentally observed. In sharp contrast to smart-clothing-related devices (e.g., textile antennas), the investigated chiral metamaterials gain their THz properties directly from the yarn-twisting enabled microhelical strings. It is envisioned that the interplay between meta-atom designs and textile manufacturing technology will lead to a new family of metadevices for complete control over the phase, amplitude, and polarization of THz radiation.