Fano resonance in terahertz parallel plate waveguide

Metamaterial-based Fano resonances are very promising for the design of sensors, lasers, and slow light devices, which are particularly important for the terahertz band where functional devices have long been lacking. However, most of the reported Fano metamaterials are designed to manipulate free-space terahertz waves. Here, we present a Fano resonance metamaterial design to manipulate the waveguide mode in a parallel plate waveguide. Different from the free-space cases, the interaction length between the waveguide mode and the Fano metamaterials can be adjusted flexibly, allowing a manipulation of the Fano resonance intensity. Moreover, we also demonstrate thin-film sensing of a monolayer graphene film with the proposed Fano resonance metamaterials. The proposed design scheme may motivate the design and fabrication of future practical devices in waveguide systems, and promote a wider application of Fano resonances.