Improvement of hybrid entanglement by dual-way photon polarization measurement

We propose a scheme of dual-way photon polarization measurement to promote the performance of post-selected polarization hybrid entanglement presented by Tiunov et al. (AIP Conference Proceedings, 020017, 2018). With on–off single-photon detectors, the scheme can mitigate the effects of two- and multi-photons on the prepared hybrid entanglement and improve its fidelity, especially for large entanglement amplitude α_f . The influences of optical loss on prepared states are also discussed. It is demonstrated that the loss on the discrete-variable channel has little effect on the prepared states, even for the loss greater than 0.9. Using squeezed vacuum as approximate coherent superposition state, we calculate the fidelity of hybrid entanglement under real experimental conditions. The results show that with same fidelity our scheme can achieve higher generation probability compared with reference Tiunov et al. (AIP Conference Proceedings, 020017, 2018), and the hybrid entanglement with medium amplitude ( α_f = 1.5 ) and high fidelity ( Fidelity > 80% ) can be produced with currently available technology.