Ge 2 Sb 2 Te 5 ‐Based Multifunctional Reconfigurable Terahertz Metamaterials with Joint Polarization Control

ABSTRACT Ge 2 Sb 2 Te 5 (GST), as a typical non‐volatile phase change material, is regarded as a strong candidate for designing reconfigurable metamaterials, while most of them reported to date operate in visible and near‐infrared regions, providing only a single‐function while neglecting polarization controllability. This article presents an integrated multifunctional GST‐based reconfigurable terahertz metamaterial with joint polarization control, consisting of an Al‐based patterned array placed on a continuous GST film separated by a middle polyimide layer. The conductivity of GST undergoes significant changes during thermal controlled phase transition process, enabling the meta‐device to dynamically switch from single‐band electromagnetically induced transparency to triple‐band near‐unity absorption. Importantly, changing incident beam polarization direction, two more functions, single‐band filtering and single‐band near‐perfect absorption, are further obtained, achieving finally four different and excellent functions, and each function could be dynamically modulated by applying different annealing temperatures, obtaining 77% amplitude modulation and up to 700% relative modulation performance, which is far superior to previously reported single‐function reconfigurable terahertz meta‐devices. Numerical simulations maintain a high degree of consistency with experimental results. Owing to the simplicity, ease‐of‐manufacturing, rich‐functional compatibility, polarization multiplexing, and excellent amplitude adjustability, the terahertz metamaterials are expected to have broad applications in optoelectronic modulators, and intelligent switches.