Demonstration of a scheme for the generation of “event-ready” entangled photon pairs from a single-photon source

We present a feasible and efficient scheme, and its proof-of-principle demonstration, of creating ``event-ready'' polarization-entangled photon pairs using only simple linear optical elements and single photons. The quality of entangled photon pairs produced in our experiment is confirmed by a strict violation of Bell's inequality. This scheme and the associated experimental techniques present a step toward linear optics quantum computation.