▎ 摘　　要

Optimization of waveguides based on surface plasmons in double-layer graphene (DLG) is presented. In contrast to previous treatments, the effects of both extrinsic scattering and intrinsic Landau damping are simultaneously considered in this analysis. We show that an optimum frequency and an optimum spacing between two graphene sheets can be found to minimize the attenuation of the plasmon propagation. The optical mode is found to be less lossy than the acoustic mode below a certain frequency, but above this frequency the situation is reversed. All observable features of DLG are corroborated by analytical or numerical results, shedding light on the possibility of compact and tunable DLG-based plasmonic waveguides. (C) 2014 AIP Publishing LLC.