Realization of a tunable double layer metamaterial absorber in terahertz

A tunable terahertz metamaterial absorber with four Dirac semimetal strips and a Dirac semimetal square is numerically studied. An absorption peak (72.5%) is achieved at resonant frequency 1.51 THz based on the local surface plasmons mode resonance on edges of Dirac semimetal square and strips synchronously. Absorption peak can be enhanced by optimizing the vertical (W1) or horizontal distance (W2) between Dirac semimetal strips and square. Moreover, new absorption resonance properties are obtained (new absorption peaks and bands). when W1 = 320 nm, a new unit cell "Structure 2" is obtained. And when W2 = 320 nm, a new unit cell "Structure 3" is also achieved. The absorption peak is also can be enhanced through changing the Fermi energy or the temperature. Finally, this proposed absorber shows high performance properties under the incidence angle 60°.