Tunable multiple narrowband polarization stable metamaterial terahertz absorbers based on dirac semi metal and phase change material VO2

Abstract

In this work, we take advantage of the characteristic of bulk Dirac semimetals (BDS) that their Fermi level can be controlled by electrostatic doping, as well as the phase transition characteristics of vanadium dioxide (VO2). Combining these two materials, we designed a terahertz metamaterial absorber with multiple control methods. It has four absorption peaks in the range of 1.5 THz to 6 THz, and the absorption rates are all above 95 %, reaching a maximum of 99.8 %. When the Fermi level of Dirac semimetals rises from 80 to 100 meV, the resonance frequency of four absorption bands of our equipment goes up, and the absorption rate remains stable, some even magnifying. The absorption peak with the largest increase in amplitude changed from 92.4 % to 99.9 %, an increase of 7.5 %. The maximum regulation range of the absorption peaks is as high as 0.34 THz. In addition, we explained the absorption principle of the equipment from two aspects: relative impedance matching and analysis of the electric field intensity distribution map, and we demonstrated the rationality of our absorber structure design through parameter scanning. Our absorber also has excellent polarization insensitivity and high refractive index sensitivity. It has potential application value in sensing, detection, medical and other fields, and our design provides new reference value for absorber designs with multiple regulation methods.

Keywords

• THz absorber
• Multiple control methods
• Electrostatic doping
• Phase transition