▎ 摘　　要

A nanoscale Fano resonator composed of a hybrid graphene disk-gold ring combination is reported in this letter. The inner narrow dipolar resonance of a discrete state induced by graphene interferes with the outside broad dipolar resonance of a continuum state induced by gold, thus forming an asymmetric Fano transparency within the absorption window. The metastructure exhibits a wide tunable band along with an excellent refractive index sensing capability of 2344 nm/RIU. The geometry adjustment modulates the spectral response giving chances to the equivalent of electromagnetically induce transparency. Moreover, the group index exceeds 760 within the transparency window enabling a potential use in slow light or light storage applications. The analytic analysis is in accordance with the numerical simulation results.