  The ability to engineer the properties of quantum optical states is essential
for quantum information processing applications. Here, we demonstrate tunable
control of spatial correlations between photon pairs produced by spontaneous
parametric down-conversion. By shaping the spatial pump beam profile in a
type-I collinear configuration, we tailor the spatial structure of coincidences
between photon pairs entangled in high dimensions, without effect on intensity.
The results highlight fundamental aspects of spatial coherence and hold
potential for the development of quantum technologies based on high-dimensional
spatial entanglement.
