title: Engineering of near-IR photon pairs to be factorable in space-time and entangled in polarization.
abstract: We present a source of near-infrared photon pairs based on the process of spontaneous parametric downconversion (SPDC), for which the joint signal-idler quantum state is designed to be factorable in the frequency-time and in the transverse position-momentum degrees of freedom. Our technique is based on the use of a broadband pump and vector group velocity matching between the pump, signal, and idler waves. We show experimentally that a source based on this technique can be configured for the generation of: i) pure heralded single photons, and ii) polarization-entangled photon pairs which are free from spectral correlations, in both cases without resorting to spectral filtering. While critical for many applications in optical quantum information processing, such a source has not previously been demonstrated.
authors.forename: Kevin
authors.initials: K
authors.lastname: Zielnicki
authors.forename: Karina
authors.initials: K
authors.lastname: Garay-Palmett
authors.forename: Radhika
authors.initials: R
authors.lastname: Dirks
authors.forename: Alfred B
authors.initials: AB
authors.lastname: U'Ren
authors.forename: Paul G
authors.initials: PG
authors.lastname: Kwiat