A double-band tunable perfect terahertz metamaterial absorber based on Dirac semimetals

• Ring-shaped THz metamaterial absorber achieves double-band perfect absorption. • Dirac material layer is used to achieve tunable absorption frequency. • The absorption property of the MA unit cell is polarization independent for TE and TM polarizations because of its central symmetry. • The coupled mode theory and COMSOL simulation software are used to analyze the MA. In this paper, a double-band tunable perfect THz metamaterial absorber (MA) is proposed, which includes a ring-shaped dielectric layer and a Dirac material layer. The simulated results indicate that the absorber has two peaks of high absorptivity at 2.02 THz and 2.49 THz, and the corresponding absorption rate is more than 99%. The Fermi energy of the BDSs could be changed to regulate the absorption peak of MA, with the change of the Fermi energy level from 55 meV to 85 meV, a dynamic adjustment of absorption rate from 90% to 99% could be effectively controlled. The absorption property of the MA unit cell is polarization independent for TE and TM polarizations because of its central symmetry. The absorber proposed not only has high absorption rate, but also has tunable absorption peak, hence it is appropriate for a series of direction of applications, such as medical sensor, optical filter and THz detecting.