Stimulated emission of polarization-entangled photons

摘要: Entangled photon pairs—discrete light quanta that exhibit non-classical correlations—play a crucial role in quantum information science (for example, demonstrations of non-locality1,2,3,4,5,6,7, teleportation8,9 and cryptography10,11,12,31). At the macroscopic optical-field level correlations can also be important, as case squeezed light13, entangled beams14,15 teleportation continuous variables16. Here we use stimulated parametric down-conversion to study states bridge gap between discrete optical correlations. We demonstrate experimentally onset laser-like action for photons, through creation amplification spin-1/2 spin-1 singlet consisting two four respectively. This entanglement structure holds great promise where there is strong demand increasing complexity.