By making use of the spatial shape of paired photons, parametric down-conversion allows the generation of
two-photon entanglement in a multidimensional Hilbert space. How much entanglement can be generated in
this way? In principle, the infinite-dimensional nature of the spatial degree of freedom renders unbounded the
amount of entanglement available. However, in practice, the specific configuration used, namely, its geometry,
the length of the nonlinear crystal, and the size of the pump beam, can severely limit the value that could be
achieved. Here we show that the use of quasi-phase-matching engineering allows one to increase the amount of
entanglement generated, reaching values of tens of ebits of entropy of entanglement under different conditions.
Our work thus opens a way to fulfill the promise of generating massive spatial entanglement under a diverse
variety of circumstances, some more favorable for its experimental implementation
By making use of the spatial shape of paired photons, parametric down-conversion allows the generation of two-photon entanglement in a multidimensional Hilbert space. How much entanglement can be generated in this way? In principle, the infinite-dimensional nature of the spatial degree of freedom renders unbounded the amount of entanglement available. However, in practice, the specific configuration used, namely, its geometry, the length of the nonlinear crystal, and the size of the pump beam, can severely limit the value that could be achieved. Here we show that the use of quasi-phase-matching engineering allows one to increase the amount of entanglement generated, reaching values of tens of ebits of entropy of entanglement under different conditions. Our work thus opens a way to fulfill the promise of generating massive spatial entanglement under a diverse variety of circumstances, some more favorable for its experimental implementation.