The authors theoretically demonstrated a tunable- and switchable-metamaterial absorber at the terahertz (THz) frequency. The proposed absorber comprising Bulk Dirac semimetal (BDS) metamaterials and vanadium dioxide (VO₂) continuous film, which can be switched between a traditional and coherent absorber by tailoring the conductivity of VO₂ film. When VO₂ is in its metallic state, the proposed absorber behaves as a traditional absorber, and it achieves an absorptivity of 92% for y-polarised incidence at 3 THz with a single illumination at normal incidence. Decreasing the conductivity of VO₂ leads to a metallic-to-insulating phase transition for the continuous VO₂ film that is accompanied by a significantly reduced absorptivity for this traditional absorber. At this time, coherent perfect absorption concept is introduced to realise a coherent absorber. The coherent absorptivity of y-polarised incidence can be dynamically modified from 0.21% to 98.5% by manipulating the mutual phase between two coherent counter-propagating incidences at the position of absorber. Furthermore, the absorption performance of traditional and coherent absorbers can be tuned individually by modifying the geometric parameters of the metamaterial structure and the Fermi energy of the BDS from 85 to 125 meV. These simulation results provide an alternative approach for the design of multi-controlled tunable absorbers in the terahertz band, exhibiting promising applications in the fields of light modulation, cloaking, and signal processing.

作者从理论上展示了一种在太赫兹 (THz) 频率下可调谐和可切换的超材料吸收器。所提出的吸收剂包括体狄拉克半金属 (BDS) 超材料和二氧化钒 (VO ₂ ) 连续膜，可通过调整 VO ₂膜的电导率在传统吸收剂和相干吸收剂之间切换。当 VO ₂处于金属状态时，所提出的吸收器的行为与传统吸收器相同，并且在 3 THz 的y偏振入射下，在垂直入射的单次照明下，它的吸收率为 92% 。降低 VO ₂的电导率导致连续 VO ₂的金属到绝缘相变这种传统吸收剂的吸收率显着降低。此时引入相干完美吸收概念来实现相干吸收体。y的相干吸收率通过操纵吸收体位置的两个相干反向传播入射之间的相互相位，偏振入射可以从 0.21% 动态修改为 98.5%。此外，传统和相干吸收器的吸收性能可以通过修改超材料结构的几何参数和 BDS 的费米能​​量从 85 到 125 meV 来单独调整。这些仿真结果为太赫兹波段多控可调吸收器的设计提供了一种替代方法，在光调制、隐身和信号处理领域展现出有前景的应用。