Tomography of spatially entangled biphotons

Correlations in light can be used for a variety of applications in metrology and imaging. Several schemes in quantum imaging rely on multi-photon absorption. Therefore a detailed knowledge of the temporal and spatial correlations of the photons used is desired. This paper investigates the correlations of space-momentum entangled biphotons generated from type II parametric down conversion. The type II generation allows for individual manipulation in each path to control the spatial modes involved in the subsequent biphoton beam creation utilizing a Hong-Ou-Mandel interference.