Tunable terahertz band-stop filter based on self-gated graphene monolayers with antidot arrays

An electrically tunable terahertz band-stop filter, which is composed of self-gated graphene monolayers with antidot arrays, is proposed and numerically investigated in this letter. Simulation results show that a pronounced resonance trough caused by graphene surface plasmons (0, 1) mode is obtained, which can be used to realize terahertz band-stop filtering efficiently. Center frequency of the resonance trough can be dynamically controlled over a broad frequency range from 6.6 to 8.6 terahertz through changing the voltage from 8.5 to 24.9 volt. Besides, the proposed filter is independent on the polarization state of incident terahertz wave as a result of its high azimuthal symmetry. The influences of structural parameters, substrate properties and misalignment of the two perforated graphene monolayers are also taken into account in further investigations for better understanding characteristics of the terahertz filter. Specifically, the proposed filter can be applied for refractive index sensing as well with a high sensitivity larger than 8.2 μm/RIU, which is potentially valuable for gas detection and so on.