Actively Tunable Plasmon-Induced Transparency via Alternately Coupled Resonators Based on Bulk Dirac Semimetal Metamaterials

We study the plasmon-induced transparency (PIT) effect in the terahertz domain based on bulk Dirac semimetal (BDS) metamaterials constructed from a cut-wire and a C-shaped resonator pair. With the help of numerical simulations and coupled mode theory, we find that the depth of the transparent window can be adjusted by the coupling distance between the cut-wire and the C-shaped resonator pair. It is further shown that by changing the Fermi level of BDS, the PIT effect can be dynamically tuned without reconstructing the geometry. Simultaneously, the metamaterial structure has excellent sensing properties, which contributes to the theoretical design of bio-chemical sensors. Finally, we further analyze the PIT effect caused by a metamaterial system consisting of a cross-shaped and four C-shaped resonators. Under the illumination of normal incident light along the x- and y-axes in the polarization direction, the device not only produces a PIT effect but also exhibits a strong resonance response consistency for light in both polarization directions, indicating that it exhibits polarization independence for incident terahertz light. This work will provide potential design value for dynamically tunable polarization-independent sensing applications.