title: Direct production of tripartite pump-signal-idler entanglement in the above-threshold optical parametric oscillator.
abstract: We calculate the quantum correlations existing among the three output fields (pump, signal, and idler) of a triply resonant nondegenerate optical parametric oscillator operating above threshold. By applying the standard criteria [P. van Loock and A. Furusawa, Phys. Rev. A 67, 052315 (2003)], we show that strong tripartite continuous-variable entanglement is present in this well-known and simple system. Furthermore, since the entanglement is generated directly from a nonlinear process, the three entangled fields can have very different frequencies, opening the way for multicolored quantum information networks.
authors.affiliation: Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, 05315-970 São Paulo, SP, Brazil.
authors.forename: A S
authors.initials: AS
authors.lastname: Villar
authors.forename: M
authors.initials: M
authors.lastname: Martinelli
authors.forename: C
authors.initials: C
authors.lastname: Fabre
authors.forename: P
authors.initials: P
authors.lastname: Nussenzveig