Dual-Spectral Plasmon-Induced Transparent Terahertz Metamaterial with Independently Tunable Amplitude and Frequency

Abstract

A bifunctional tunable metamaterial composed of pattern metal structure, graphene, and strontium titanate (STO) film is proposed and studied numerically and theoretically. The dual plasmon-induced transparency (PIT) window is obtained by coupling the bright state cut wire (CW) and two pairs of dark state dual symmetric semiring resonators (DSSRs) with different parameters. Correspondingly, slow light effect can also be realized. When shifting independently, the Fermi level of the graphene strips, the amplitudes of the two PIT transparency windows and slow light effect can be tuned, respectively. In addition, when independently tuning the temperature of the metamaterial, the frequency of the dual PIT windows and slow light effect can be tuned. The physical mechanism of the dual-PIT was analyzed theoretically by using a three-harmonic oscillator model. The results show that the regulation function of the PIT peak results from the change of the oscillation damping at the dark state DSSRs by tuning conductivity of graphene. Our design presents a new structure to realize the bifunctional optical switch and slow light.

Flexibly manipulating the polarization independent plasmon-induced transparency in a graphene and strontium titanate integrated terahertz metasurface

“…And the change in substrate permittivity will result in the resonance shift in a metasurface [19]. Neglecting the temperature on graphene conductivity [18,27], figure 7 shows the transmission spectra of the proposed metasurface with the Fermi energy configuration of 0.6 eV & 1.0 eV at different environmental temperatures. When the temperature increase from 200 K to 400K, the PIT spectrum undergoes a blueshift.…”

Symmetry-Engineered Dual Plasmon-Induced Transparency via Triple Bright Modes in Graphene Metasurfaces

“…By the excitation of two bright modes simultaneously in the graphene metasurfaces, the tunable PIT window can also be achieved [24][25][26][27]. Additionally, the dynamic control of double PITs is possible in the graphene-based metasurfaces through the coupling between one bright mode and two dark modes [28], or two bright modes and one dark mode [29,30]. However, PIT arising from the triple bright modes has not been studied in graphene-based metasurfaces.…”