Dynamically Switchable Polarization-Independent Triple-Band Perfect Metamaterial Absorber Using a Phase-Change Material in the Mid-Infrared (MIR) Region

• Main Authors: Dongdong Xu, Fenping Cui, Gaige Zheng
• Format: Article
• Language: English
• Published: MDPI AG 2021-05-01
• Series: Micromachines
• Subjects: germanium-antimony-tellurium; triple-band absorber; mid-infrared regime; near unity absorption
• Online Access: https://www.mdpi.com/2072-666X/12/5/548

A tunable metamaterial absorber (MMA) by reversible phase transitions in a mid-infrared regime is theoretically investigated. The absorber is composed of a molybdenum (Mo)-germanium-antimony-tellurium (Ge₂Sb₂Te₅, GST)-Mo nanodisk structure superimposed on the GST-Al₂O₃ (aluminum oxide)-Mo film. Studies have shown that the combination of the inlaid metal-medium dielectric waveguide mode and the resonant cavity mode and the excitation of the propagating surface plasmon mode are the main reasons for the formation of the triple-band high absorption. Additionally, through the reversible phase change, the transition from high absorption to high reflection in the mid-infrared region is realized. The symmetry of the absorber eliminates the polarization dependence, and the near unity absorption efficiency can be maintained by incidence angles up to 60°. The presented method will enhance the functionality of the absorber and has the potential for the applications that require active control over light absorption.