Photon-pair generation and quantum measurements with metasurfaces

We present the theoretical and experimental advances of our group on quantum photon-pair generation through spontaneous parametric down-conversion in nonlinear metasurfaces, underpinning quantum entanglement engineering at a sub-wavelength scale for photon shaping with tailored polarization and spatial correlations. In particular, we demonstrate experimentally the generation of spatially entangled photon pairs through spontaneous parametric down-conversion from a metasurface incorporating a nonlinear thin film of lithium niobate covered by a silica meta-grating and achieve precise control of the emission angle of photons. We also outline the applications of metasurfaces quantum imaging combining ghost and all-optical scanning at infrared wavelengths and perform single-shot characterization of the indistinguishability between two photons.