▎ 摘　　要

In this study, the orbital angular momentum (OAM) sidebands of Laguer re-Gauss beams reflecting on graphene metasurfaces are investigated. Upon reflection, vortex beams carrying orbital angular momentum will acquire sidebands, whose relative intensity varies depending on the Fermi energy, the external magnetic field, and/or the wave frequency. The relative intensity of the sideband OAM modes locally has a small trough for s-polarized beams at the topological transition point between the hyperbolic and elliptic topology. Energy can transfer from the central mode to the neighboring OAM modes increasing the topologic charge l. When the electric field of the incident s-polarized light occurs along the low energy dissipation direction of the graphene metasurfaces, it is helpful for the mode transformation of vortex beams. When the electric field of the incident s-polarized light occurs along the high energy dissipation direction, it is beneficial to suppressing crosstalk of different sidemodes in terahertz communication.