Crossover from plasmonic analogue of Fano resonance to Autler-Townes splitting in a double guide mode resonances system

The plasmonic analogy from Fano resonance to Autler-Townes splitting (ATS) in mid-infrared spectral range is observed assisted by a dual parallel graphene-coated grating structure. The analytical derivation exhibits a height-dependent resonance which is crucial for discerning Fano resonance from ATS. The mechanism of generating a transparency window seeks a trade-off between Fano resonance and ATS at threshold height. While within the critical height, Fano resonance dominates. The Akaike Information Criterion test is used to discern these two effects quantitatively. Moreover, the device pronounces a good tunability accompanied with a slowing light application. Our ideas open up a new insight view of designing or constructing highly integrated, multi-functional graphene-based metamaterials in nanoscale.