Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Published Online March 28, 2002
Science DOI: 10.1126/science.1068972

Reports

Submitted on December 13, 2001
Accepted on March 13, 2002

Experimental Quantum Cloning of Single Photons

Antía Lamas-Linares 1*, Christoph Simon 1, John C. Howell 2, Dik Bouwmeester 3

1 Centre for Quantum Computation, University of Oxford,Parks Road, Oxford OX1 3PU, UK.
2 Department of Physics, University of Rochester, Rochester, NY14627, USA; Centre for Quantum Computation, University of Oxford,Parks Road, Oxford OX1 3PU, UK.
3 Centre for Quantum Computation, University of Oxford,Parks Road, Oxford OX1 3PU, UK; Department of Physics, University of California at Santa Barbara.

* To whom correspondence should be addressed. E-mail: a.lamas{at}qubit.org.

Although perfect copying of unknown quantum systems is forbidden by the laws of quantum mechanics, approximate cloning is possible. A natural way of realizing quantum cloning of photons is by stimulated emission. In this context the fundamental quantum limit to the quality of the clones is imposed by the unavoidable presence of spontaneous emission. In our experiment a single input photon stimulates the emission of additional photons from a source based on parametric down-conversion. This leads to the production of quantum clones with near optimal fidelity. We also demonstrate universality of the copying procedure by showing that the same fidelity is achieved for arbitrary input states.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Quantum-to-Classical Transition with Single-Photon-Added Coherent States of Light.
A. Zavatta, S. Viciani, and M. Bellini (2004)
Science 306, 660-662
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)