Realization Of Hyperentangled Two-Photon States

We report on the experimental realization of hyperentangled two-photon states, entangled in polarization and momentum. These states are produced by a high-brilliance parametric source of entangled photon pairs with peculiar characteristics of flexibility in terms of state generation. The quality of the entanglement in the two degrees of freedom has been tested by multimode Hong-Ou-Mandel interferometry.