Picture of wind turbine against blue sky

Open Access research with a real impact...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs.

The Energy Systems Research Unit (ESRU) within Strathclyde's Department of Mechanical and Aerospace Engineering is producing Open Access research that can help society deploy and optimise renewable energy systems, such as wind turbine technology.

Explore wind turbine research in Strathprints

Explore all of Strathclyde's Open Access research content

Precise quantum tomography of photon pairs with entangled orbital angular momentum

Jack, B. and Leach, J. and Ritsch, H. and Barnett, S.M. and Padgett, M.J. and Franke-Arnold, S. (2009) Precise quantum tomography of photon pairs with entangled orbital angular momentum. New Journal of Physics, 11. pp. 1-12. ISSN 1367-2630

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

We report a high fidelity tomographic reconstruction of the quantum state of photon pairs generated by parametric down-conversion with orbital angular momentum (OAM) entanglement. Our tomography method allows us to estimate an upper and lower bound for the entanglement between the down-converted photons. We investigate the two-dimensional state subspace defined by the OAM states ± and superpositions thereof, with =1, 2, ..., 30. We find that the reconstructed density matrix, even for OAMs up to around =20, is close to that of a maximally entangled Bell state with a fidelity in the range between F=0.979 and F=0.814. This demonstrates that, although the single count-rate diminishes with increasing , entanglement persists in a large dimensional state space.