Plasmon-enhanced optical nonlinearity in graphene nanomeshes

Using the density-matrix formalism, we show that graphene nanomeshes (GNMs)-graphene sheets patterned with antidots-have large plasmon-enhanced nonlinear optical response. GNMs can be designed to behave as quasi-one-dimensional plasmonic crystals in which plasmons with large propagation lengths are efficiently excited. The associated third-order Kerr and third-harmonic-generation susceptibility can be as high as 10(-7) and 10(-9) m(2) V-2, respectively, over the mid-to-near-infrared frequency range. Furthermore, carrier-density tuning in GNMs can flip the propagation direction of plasmonic waves and enables bidirectional switching of optical signals.