Feshbach blockade: Single-photon nonlinear optics using resonantly enhanced cavity polariton scattering from biexciton states

We theoretically demonstrate how the resonant coupling between a pair of cavity polaritons and a biexciton state can lead to a large single-photon Kerr nonlinearity in a semiconductor solid-state system. A fully analytical model of the scattering process between a pair of cavity polaritons is developed, which explicitly includes the biexcitonic intermediate state. A dramatic enhancement of the polariton-polariton interactions is predicted in the vicinity of the biexciton Feshbach resonance. Application to the generation of non-classical light from polariton dots is discussed.