Tunable dual‐spectral plasmon‐induced transparency in terahertz Dirac semimetal metamaterials

We have numerically studied a tunable dual-spectral plasmon-induced transparency metamaterial structure based on Dirac semimetal films in the terahertz region. The structure was composed of three length-variant parallel coplanar strips. The dual-spectral plasmon-induced transparency is mainly induced by the bright-bright modes coupling between neighboring Dirac semimetal strips. By adjusting the Fermi energies of Dirac semimetal strips, the individual and synchronous modulation of the dual-transparency window in resonance frequency, bandwidth and strength can be obtained, respectively. Simultaneous change of the Fermi energies of all the strips can achieve an overall frequency shift of the dual-transparency window, with the frequency modulation depth of 21.7% and 20.0%, respectively. The maximum group delays of 5.26 and 3.57 ps for each window were calculated in our proposed structure. The simulation results demonstrated the potential of the proposed structure to expand the applications for slow-light systems, filters, and switchers in the terahertz region.