Observation of two-photon speckle patterns

Phys Rev Lett. 2010 Apr 30;104(17):173601. doi: 10.1103/PhysRevLett.104.173601. Epub 2010 Apr 27.


We report the observation of speckle patterns in quantum correlations within light that is scattered by a disordered medium. The random medium is illuminated with spatially entangled photon pairs, and fourth-order speckle patterns are spatially resolved by two independently scanning detectors. Spatial entanglement gives two-photon speckle a much richer structure than ordinary one-photon speckle. Our experiments demonstrate that two-photon speckle from a surface scatterer and a volume scatterer look entirely different.