▎ 摘　　要

In this paper, the Goos-Hanchen (GH) shift resulting from the graphene surface plasmon in a modified Otto configuration is investigated theoretically. Through analysis the electrical field at the graphene interface, we found that the GH shift can be significantly enlarged negatively due to the exciting of surface plasmon resonance of graphene in terahertz efficiently. The GH shifts can be switched from negative to positive by harnessing the optical properties of graphene, and the negative GH shift can be actively tuned through the Fermi energy and the relaxation time of the graphene, or by controlling the distance between the coupling prism and the graphene layer. These tunable GH shifts are promising for fabricating graphene-based optical shift devices and other applications in the terahertz regime.