Design and fabrication of metastructures for terahertz applications

Abstract

This work focuses on the design of three specific metastructures using the commercial simulation software CST Studio Suite. The first is a wire-grid polarizer, an essential component for terahertz (THz) time-domain spectroscopic ellipsometry. Wire-grid polarizers were fabricated using direct laser writing lithography and physical vapor deposition, and their functionality was experimentally validated through terahertz time-domain spectroscopy. The second is a metalens, a flat focusing device replacing bulky traditional optics and enabling high-power THz output from spintronic THz emitters. The third is a chiral metastructure, an artificial chiral material exhibiting strong optical activity, intended as a reference for other optically active materials in the THz range. For the latter two metastructures, the fabrication strategies are discussed based on advanced lithographic techniques.