▎ 摘　　要

A novel structure with bilayer hybrid graphene/metal (G/M) gratings to realize tunable double Fano resonances has been proposed. Different band gaps can be obtained by applying voltages on the bilayer graphenes. Due to the tunability of the hybrid structure, two different resonances are separately tuned under various parametric conditions. The Fano resonances are produced by the interaction between the metal and graphene gratings, the related mechanism is investigated by the electric field distribution and transmission phase. The superior characteristics of the separately tunable double Fano resonances indicate a promising application in THz optical devices. (C) 2017 Elsevier Ltd. All rights reserved.