Design of an ultra-wideband switchable terahertz metamaterial absorber using a VO ₂ transversally open ring structure

Abstract

This paper proposes a switchable terahertz (THz) metamaterial absorber based on vanadium dioxide (VO ₂), which can not only realize ultra-wideband (UWB) perfect absorption in the THz range, but also has the ability to adjust the absorption rate by regulating the conductivity of VO ₂. When VO ₂ conductivity is 2×10 ⁵S/m, the designed UWB absorber can achieve over 90% absorption in the frequency range of 2.62–10 THz. Simultaneously, the peak absorption intensity of the absorber can also be regulated dynamically ranging from 100% to 0.8% when the conductivity of VO ₂ is adjusted to change from 2×10 ⁵ to 20 S/m. Furthermore, the designed absorber has the advantages of polarization insensitivity and wide-angle absorption. For TE polarization with an incident angle of less than 40° and TM polarization with an incident angle of less than 60°, the absorption rate remains above 90%. The UWB absorber has the advantages of simple structure, wide tuning range, and good absorption performance, and it has potential applications in many fields such as THz filtering, invisibility, sensing, optoelectronic switches, and so on.