title: Pure single photon generation by type-I PDC with backward-wave amplification.
abstract: We explore a promising method of generating pure heralded single photons. Our approach is based on parametric down-conversion in a periodically-poled waveguide. However, unlike conventional downconversion sources, the photon pairs are counter-propagating: one travels with the pump beam in the forward direction while the other is backpropagating towards the laser source. Our calculations reveal that these downconverted two-photon states carry minimal spectral correlations within each photon-pair. This approach offers the possibility to employ a new range of downconversion processes and materials like PPLN (previously considered unsuitable due to its unfavorable phasematching properties) to produce heralded pure single photons over a broad frequency range.
authors.affiliation: Max-Planck Institute for the Science of Light Günther Scharowsky-Str.1 / Bau 24, 91054 Erlangen, Germany. Andreas.Christ@mpl.mpg.de
authors.forename: A
authors.initials: A
authors.lastname: Christ
authors.forename: A
authors.initials: A
authors.lastname: Eckstein
authors.forename: P J
authors.initials: PJ
authors.lastname: Mosley
authors.forename: C
authors.initials: C
authors.lastname: Silberhorn