Phys. Rev. Lett. 111, 247401 (2013)

Michael Gullans from Harvard University in the USA and co-workers from the research institutes ICFO and ICREA in Barcelona, Spain, have theoretically predicted that graphene plasmonic nanostructures should be able to produce nonlinear optical effects when driven at the few- or single-photon level. Such effects usually require much stronger light signals, but the researchers say that the combination of plasmonic-induced electromagnetic field enhancement and the intrinsic nonlinearity of graphene can lower the threshold to the level that quantum nonlinear optics becomes possible. It is predicted that, under realistic conditions, deterministic interaction between two single plasmons will be possible; this may make it possible to realize a single-photon switch. The approach has implications not only for classical nonlinear photonics but also for quantum optics.