Polarization entanglement and quantum beats of photon pairs from four-wave mixing in a cold 87 Rb ensemble
Gurpreet Kaur Gulati, Bharath Srivathsan, Brenda Chng, Alessandro Ceré, Christian Kurtsiefer · New Journal of Physics · 2015
We characterize correlations in polarization and time of photon pairs generated from a cold cloud of 87 Rb atoms via a four-wave mixing process in a cascade level scheme. Quantum state tomography reveals entangled polarization states of high purity for each of the decay paths through two different intermediate hyperfine levels. When allowing both decay paths, we observe quantum beats in time-resolved correlation measurements.