TY - JOUR

T1 - Precise quantum tomography of photon pairs with entangled orbital angular momentum

AU - Jack, B.

AU - Leach, J.

AU - Ritsch, H.

AU - Barnett, S. M.

AU - Padgett, M. J.

AU - Franke-Arnold, S.

PY - 2009/10

Y1 - 2009/10

N2 - 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 +/-l and superpositions thereof, with l = 1, 2, ... , 30. We find that the reconstructed density matrix, even for OAMs up to around l = 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 l, entanglement persists in a large dimensional state space.

AB - 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 +/-l and superpositions thereof, with l = 1, 2, ... , 30. We find that the reconstructed density matrix, even for OAMs up to around l = 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 l, entanglement persists in a large dimensional state space.

U2 - 10.1088/1367-2630/11/10/103024

DO - 10.1088/1367-2630/11/10/103024

M3 - Article

VL - 11

JO - New Journal of Physics

JF - New Journal of Physics

SN - 1367-2630

M1 - 103024

ER -