title: Quantum interference of ultrastable twin optical beams.
abstract: We report the first measurement of the quantum phase-difference noise of an ultrastable nondegenerate optical parametric oscillator that emits twin beams classically phase locked at exact frequency degeneracy. The measurement illustrates the property of a lossless balanced beam splitter to convert number-difference squeezing into phase-difference squeezing, and thus provides indirect evidence for Heisenberg-limited interferometry using twin beams. This experiment is a generalization of the Hong-Ou-Mandel interference effect for continuous variables and constitutes a milestone towards continuous-variable entanglement of bright, ultrastable nondegenerate beams.
authors.affiliation: Department of Physics, University of Virginia, 382 McCormick Road, Charlottesville, Virginia 22904-4714, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Feng
authors.forename: Olivier
authors.initials: O
authors.lastname: Pfister