High-Q terahertz Fano-like resonance effect based on robust metamaterial resonator

It is well known that Fano effect usually requires the introduction of asymmetric (or breaking) in their structure designs. The smaller the degree of breaking, the more obvious the Fano effect. However, the small degree of breaking demands extremely precise manufacturing capabilities and levels. This paper proposes a novel robust metallic array structure that can achieve a Fano-like effect with a high Q-factor as 73, consisting of a square patch and a closed-ring resonator. This distinct Fano-like resonance originates from the interactions of quadrupole resonance mode and dipole resonance mode. Moreover, the effect of the size and conductivity of the square patch on the Fano effect are discussed, and the sensing performance of this structure is also discussed. These results will pave the way for designing practical sensors and optical switches in the terahertz frequency range.