title: Generation and characterization of multimode quantum frequency combs.
abstract: Multimode nonclassical states of light are an essential resource in quantum computation with continuous variables, for example, in cluster state computation. We report in this Letter the first experimental evidence of a multimode nonclassical frequency comb in a femtosecond synchronously pumped optical parametric oscillator. In addition to a global reduction of its quantum intensity fluctuations, the system features quantum correlations between different parts of its frequency spectrum. This allows us to show that the frequency comb is composed of several uncorrelated eigenmodes having specific spectral shapes, two of them at least being squeezed, and to characterize their spectral shapes.
authors.affiliation: Laboratoire Kastler Brossel, Université Pierre et Marie Curie-Paris 6, ENS, CNRS, Paris, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Pinel
authors.forename: Pu
authors.initials: P
authors.lastname: Jian
authors.forename: Renné
authors.initials: R
authors.lastname: Medeiros de Araújo
authors.forename: Jinxia
authors.initials: J
authors.lastname: Feng
authors.forename: Benoît
authors.initials: B
authors.lastname: Chalopin
authors.forename: Claude
authors.initials: C
authors.lastname: Fabre
authors.forename: Nicolas
authors.initials: N
authors.lastname: Treps