Demonstration of efficient scheme for generation of "Event Ready"   entangled photon pairs from single photon source
  We present a feasible and efficient scheme, and its proof-of-principle demonstration, of creating entangled photon pairs in an event-ready way using only simple linear optical elements and single photons. The quality of entangled photon pair produced in our experiment is confirmed by a strict violation of Bell's inequality. This scheme and the associated experimental techniques present an important step toward linear optics quantum computation. 
Qiang Zhang, Xiao-Hui Bao, Chao-Yang Lu, Xiao-Qi Zhou, Tao Yang, Terry   Rudolph, Jian-Wei Pan