The subject matter of this specification can be embodied in, among other things, a graphene plasmon resonator that includes a planar patterned layer having a collection of electrically conductive segments, and a collection of dielectric segments, each dielectric segment defined between a corresponding pair of the electrically conductive segments, a graphene layer substantially parallel to the planar patterned layer and overlapping the collection of electrically conductive segments, and a planar dielectric layer between the planar patterned layer and the graphene layer.