Hectometer Revivals of Quantum Interference

The Hong-Ou-Mandel (HOM) effect is the most famous signature of nonclassical interference. This inherently quantum effect has a vast amount of applications including photonic entangling gates, measurement processes and femtosecond spectroscopy and its sensitivity to distinguishability can be exploited as a precise sensor for phase shifts or temporal and spatial displacements. Traditional single photon sources exhibit a single dip with a width on the order of millimetres to centimetres, however, the possibility to significantly extend this distance opens up new applications in both metrology and quantum networks.