Tunable multiple plasmon-induced transparency in a simple terahertz Dirac semimetal based metamaterial

We proposed a bulk Dirac semimetal (BDS) based metamaterial that consists of two identical vertical BDS rods and two horizontal BDS rods with different lengths. Numerical simulation results show that the proposed structure can realize the tunable multiple plasmon-induced transparency (multi-PIT) effect. The multi-PIT effect is mainly attributed to the introduction of the bonding mode simply by manipulating the lengths of horizontal rods. By changing the Fermi energy of the BDS, the tunable multi-PIT spectrum and tunable multi-band group delay can be achieved. The multi-PIT peaks are also sensitive to the background refractive index and can lead high FOM values of 16, 50.9 and 10.6, respectively. The proposed structure is desirable for designing tunable THz sensors, modulators and slow light devices.