Entangled pulses of 105 photons

21.06.2013, 00:00

Newsletter 6

Recently we have produced bright pulses, each containing 105 photons, that manifest macroscopic entanglement. Although the photons emitted into beams A and B are randomly polarised, their polarisation states are strictly correlated. This means that the number of photons in any polarization mode of beam A is exactly equal to the number of orthogonally polarised photons in beam B. To verify this entanglement, we used a simple criterion: for a separable (non-entangled) state, the sum of the variances for three Stokes observables normalized to the mean photon number cannot be less than 2. The measurement, performed jointly on beams A and B, shows violation of this condition by more than five standard deviations and thus confirms entanglement. The violation occurs only in a certain range of the diameter D1 of an aperture providing proper mode matching between beams A and B.

Contact: maria.chekhova(at)mpl.mpg(dot)de
Group: Single Photon Technology (TDSU)
Reference: T. Sh. Iskhakov et al., Phys. Rev. Lett. 109, 150502 (2012).