Letter abstract

Nature Photonics 4, 553 - 556 (2010)
Published online: 27 June 2010 | doi:10.1038/nphoton.2010.156

Subject Categories: Lasers, LEDs and light sources | Quantum optics

Heralded generation of entangled photon pairs

Stefanie Barz1,2,3, Gunther Cronenberg1,2,3, Anton Zeilinger1,2 & Philip Walther1,2

Entangled photons are a crucial resource for quantum communication and linear optical quantum computation. Unfortunately, the applicability of many photon-based schemes is limited due to the stochastic character of the photon sources. Therefore, a worldwide effort has focused on overcoming the limitation of probabilistic emission by generating two-photon entangled states conditioned on the detection of auxiliary photons. Here we present the first heralded generation of photon states that are maximally entangled in polarization with linear optics and standard photon detection from spontaneous parametric downconversion1. We use the downconversion state corresponding to the generation of three photon pairs, where the coincident detection of four auxiliary photons unambiguously heralds the successful preparation of the entangled state2. This controlled generation of entangled photon states is a significant step towards the applicability of a linear optics quantum network, in particular for entanglement swapping, quantum teleportation, quantum cryptography and scalable approaches towards photonics-based quantum computing3.

  1. Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
  2. Institute for Quantum Optics and Quantum Information (IQOQI), Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria
  3. These authors contributed equally to this work

Correspondence to: Philip Walther1,2 e-mail: philip.walther@univie.ac.at


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