title: Statistically background-free, phase-preserving parametric up-conversion with faint light.
abstract: We demonstrate up-conversion with no statistically significant background photons and a dynamic range of 15 decades. Near-infrared 920 nm photons were converted into the visible at 577 nm using periodically poled lithium niobate waveguides pumped by a 1550 nm laser. In addition to achieving statistically noiseless frequency up-conversion, we report a high degree of phase preservation (with fringe visibilities ≥ 0.97) at the single-photon level using an up-converting Mach-Zehnder interferometer. This background-free process opens a path to single-photon detection with no intrinsic dark count. Combined with a demonstrated photon-number preserving property of an up-converter, this work demonstrates the feasibility of noiseless frequency up-conversion of entangled photon pairs.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Cheng
authors.forename: Tim
authors.initials: T
authors.lastname: Thomay
authors.forename: Glenn S
authors.initials: GS
authors.lastname: Solomon
authors.forename: Alan L
authors.initials: AL
authors.lastname: Migdall
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Polyakov