  We show that the electromagnetic forces generated by the excitations of a
mode in graphene-based optomechanical systems are highly tunable by varying the
graphene chemical potential, and orders of magnitude stronger than usual
non-graphene-based devices, in both attractive and repulsive regimes. We
analyze coupled waveguides made of two parallel graphene sheets, either
suspended or supported by dielectric slabs, and study the interplay between the
light-induced force and the Casimir-Lifshitz interaction. These findings pave
the way to advanced possibilities of control and fast modulation for
optomechanical devices and sensors at the nano- and micro-scales.
