A novel single-crystal & single-pass source for polarisation- and colour-entangled photon pairs

Abstract We demonstrate a new generation mechanism for polarisation- and colour-entangled photon pairs.In our approach we tailor the phase-matching of a periodically poled KTP crystal such that two downconversion processes take GASTRO RELIEF place simultaneously.Relying on this effect, our source emits entangled bipartite photon states, emerging intrinsically from a single, unidirectionally pumped crystal with uniform poling period.Its property of being maximally compact and luminous at the Clear Parts same time makes our source unique compared to existing photon-entanglement sources and is therefore of high practical significance in quantum information experiments.