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Q: Quantenoptik
Q 9: Poster: Quantum Information
Q 9.9: Poster
Tuesday, April 3, 2001, 12:30–15:00, AT2
Bright EPR-entangled beams — •Christine Silberhorn1, Michael Langer1, Ping Koy Lam2,1, Natalia Korolkova1, and Gerd Leuchs1 — 1Zentrum für Moderne Optik, Universität Erlangen, Staudtstr. 7 / B2, 91058 Erlangen, Germany — 2Department of Physics, Faculty of Science, ANU, ACT 0200, Australia
We report on a new source for multi-photon EPR-entanglement [1]. For the generation of bright entangled beams the Kerr nonlinearity in an optical fibre is employed to produce two independently amplitude squeezed beams. To transform the squeezing of the beams into EPR-entanglement the light fields are superimposed at a 50:50 beam splitter. The quality of the EPR-entanglement generated in this interference depends on the initial squeezing of the two input beams. In the experiment the 130 fs pulses are injected into an asymmetric fibre Sagnac interferometer. This is operated simultaneously at two orthogonal polarizations to obtain the two squeezed beams for the interference. The pulses at the output ports of the beam splitter show an anti-correlation of 4.0 ± 0.2 dB below the quantum limit for the amplitude and a correlation of 4.0 ± 0.4 dB for the phase quadrature. For the demonstration of EPR-entanglement the product of the inferred uncertainties for one beam is calculated to be 0.64 ± 0.08 well below the EPR limit of unity. The state is proven to fulfill the Peres-Horodecki criterion for nonseparability of continuous variable systems by the sum of the inferred variances 0.40 ± 0.02 < 1 [2].
[1] Ch. Silberhorn et al, PRL, submitted (2000).
[2] M. D. Reid et al, PRL 60,2731 (1988); L. Duan, et al, PRL 84, 2722, (2000); Simon, PRL 84, 2726, (2000).