Branch-entangled polariton pairs inplanar microcavities and photonic wires
Résumé
A scheme is proposed for the generation ofbranch-entangled pairs of microcavity polaritons throughspontaneous inter-branch parametric scattering.Branch-entanglement is achievable when there are two twinprocesses, where the role of signal and idler can be exchangedbetween two different polariton branches. Branch-entanglement ofpolariton pairs can lead to the emission of frequency-entangledphoton pairs out of the microcavity. In planar microcavities, thenecessary phase-matching conditions are fulfilled for pumping ofthe upper polariton branch at an arbitrary in-plane wave-vector.The important role of nonlinear losses due to pair scattering intohigh-momentum exciton states is evaluated. The results show thatthe lack of protection of the pump polaritons in the upper branchis critical. In photonic wires, branch-entanglement ofone-dimensional polaritons is achievable when the pump excites alower polariton sub-branch at normal incidence, providingprotection from the exciton reservoir.