Tunable phonon-indued transparency in bilayer graphene plasmonic structures

Electromagnetically induced transparency (EIT) has been extensively studied in atomic systems. EIT-like phenomena have also been demonstrated in classical systems, such as plasmonic and opto-mechanical systems. Here we present an EIT-like behavior in AB stacking bilayer graphene nanoribbons, where the destructive interference of an infrared active phonon mode and a plasmon mode induces an absorption transparency in the vicinity of the phonon frequency. More importantly, this phonon-induced transparency can be tuned by electrostatic or chemical doping. This kind of tunability is lacking in many of the systems with EIT-like property. The phonon-induced transparency is also accompanied by the slow light effect and a light group index as large as 500 has been inferred from our data. Bilayer graphene provides us a unique opportunity to explore EIT-like phenomena involving phonons and plasmons.