  We show that rhombohedral multilayer graphene supports topological frequency
conversion, whereby a fraction of electrons transfer energy between two
monochromatic light sources at a quantized rate. The pristine nature and gate
tunability of these materials, along with a Berry curvature that directly
couples to electric fields, make them ideal platforms for the experimental
realization of topological frequency conversion. Among the rhombohedral family,
we find that Bernal bilayer graphene appears most promising for THz-scale
applications due to lower dissipation. We discuss strategies to circumvent
cancellations between the two valleys of graphene and to minimize dissipative
losses using commensurate frequencies, thus opening a potential pathway for net
amplification.
