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

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 degrees. The presented method will enhance the functionality of the absorber and has the potential for the applications that require active control over light absorption.

Automated summary

A tunable metamaterial absorber in the mid-infrared regime was theoretically investigated, revealing that the combination of inlaid metal-medium dielectric waveguide mode and resonant cavity mode, as well as excitation of propagating surface plasmon mode, are the main reasons for triple-band high absorption. Through reversible phase transitions, the transition from high absorption to high reflection in the mid-infrared region was achieved, with near unity absorption efficiency maintained by incidence angles up to 60 degrees.