Letter abstract


Nature Photonics 4, 549 - 552 (2010)
Published online: 30 May 2010 | doi:10.1038/nphoton.2010.123

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

Experimental demonstration of a heralded entanglement source

Claudia Wagenknecht1,4, Che-Ming Li1,2,4, Andreas Reingruber1, Xiao-Hui Bao1,3, Alexander Goebel1, Yu-Ao Chen1,3, Qiang Zhang1, Kai Chen3 & Jian-Wei Pan1,3


The heralded generation of entangled states is a long-standing goal in quantum information processing, because it is indispensable for a number of quantum protocols1, 2. Polarization entangled photon pairs are usually generated through spontaneous parametric down-conversion3, but the emission is probabilistic. Their applications are generally accompanied by post-selection and destructive photon detection. Here, we report a source of entanglement generated in an event-ready manner by conditioned detection of auxiliary photons4. This scheme benefits from the stable and robust properties of spontaneous parametric down-conversion and requires only modest experimental efforts. It is flexible and allows the preparation efficiency to be significantly improved by using beamsplitters with different transmission ratios. We have achieved a fidelity better than 87% and a state preparation efficiency of 45% for the source. This could offer promise in essential photonics-based quantum information tasks, and particularly in enabling optical quantum computing by reducing dramatically the computational overhead5, 6.

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  1. Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Philosophenweg 12, 69120 Heidelberg, Germany
  2. Department of Physics and National Center for Theoretical Sciences, National Cheng Kung University, Tainan 701, Taiwan
  3. Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
  4. These authors contributed equally to this work

Correspondence to: Kai Chen3 e-mail: kaichen@ustc.edu.cn

Correspondence to: Jian-Wei Pan1,3 e-mail: jian-wei.pan@physi.uni-heidelberg.de



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