Heralded Single Photons Pairs

Single-photon sources are important resources for many quantum applications, such as quantum communications, photonic quantum computation quantum metrology. Heralded single-photon sources create correlated photon-pair produced in the SPDC process. A single photon’s presence is “heralded” by the detection of its twin photon. Indistinguishable heralded photons, i.e., identical photons, are desirable because they can exhibit multi-photon interference that is central to many quantum information applications