A triple-band terahertz metamaterial absorber based on buck Dirac semimetals

In this paper, a triple-band terahertz metamaterial absorber (MA) based on buck Dirac semimetals (BDSs) is proposed, which consists of a windmill-shaped element in a square ring layer, a dielectric layer, and a BDSs layer. The MA unit cell is investigated at normal and oblique incidence angle for both transverse electric (TE) and transverse magnetic (TM) polarizations. The simulation results show that the MA has three high absorption peaks at 0.80 THz, 1.72 THz, and 3.38 THz. The corresponding peak absorbance are 99.43%, 99.92% and 99.58%, respectively. Moreover, the absorption peaks of MA can be tuned by adjusting the Fermi energy of the BDSs. And the density of electric field, the magnetic field, and surface current distributions of the MA are given to reveal the absorption mechanism. According to the simulation results, the designed MA not only has high absorbance, but also insensitive to polarizations. Hence it is favorable for various applications, such as terahertz detecting, radar stealth and bio-chemical sensor.