Switchable triple plasmon-induced transparency in graphene sandwich metamaterial structures

In this research, a metamaterial structure composed of graphene sandwich structure is put forward to achieve triple plasmon-induced transparency. This phenomenon is generated by bright-bright modes interaction in the proposed structure, and the results calculated though couple mode theory are consistent with the simulation ones using finite difference time domain method. In addition, the effects of graphene Fermi level and scattering rate on the transmission spectrum are also discussed. It is found that the five-fold switching effects are achieved with the modulation depths (MDs) of 92%, 91%, 95%, 90% and 94%, respectively. What is more, the different graphene strip can also be adjusted by changing Fermi levels to achieve the switching effects with the MDs of 98% and 97%. This model has the prospect to be applied in multi-functional modulators and optical switches in terahertz band.