Restoring and tailoring very high dimensional spatial entanglement of a biphoton state transmitted through a scattering medium

Abstract

We report experimental results where a momentum entangled biphoton state with a giant dimensionality of 8000 is retrieved and manipulated when only one photon of the pair is transmitted through a thin scattering medium. For this purpose, the transmission matrix of the complex medium is first measured with a phase-shifting interferometry measurement method using a spatial light modulator (SLM) illuminated with a laser source. From this matrix, different phase masks are calculated and addressed on the SLM to spatially control the focusing of the laser through the complex medium. These same masks are used to manipulate the phase of the biphoton wave function transmitted by the thin diffuser in order to restore and control in the same way the momentum correlations between the far-field images of twin beams issued from strongly spatial-multi-mode spontaneous parametric down conversion.

Manipulation and certification of high-dimensional entanglement through a scattering medium

“…These techniques have recently been applied to highdimensional spatially-entangled photon pairs. Proof-ofprinciple experiments include their transmission through thin static [23,24] and dynamic diffusers [25], and multimode fibers [26]. However, these demonstrations have…”

“…several limits. In references [23][24][25], the authors demonstrated only the recovery of spatial correlations after the medium by performing measurements in a single spatial basis, but not entanglement itself. In reference [26], entanglement was certified at the output up to six dimensions.…”