Certifying spatial entanglement between non-degenerate photon pairs with a camera

Abstract

We investigate transverse spatial entanglement between photon pairs of different wavelengths using a camera-based coincidence technique. By adapting the correlation measurements to the photons frequencies, we certify the presence of entanglement between the pairs through violation of an Einstein-Podolsky-Rosen criterion. Additionally, we examine how parameters such as pump waist and crystal length influence these correlations. Our results highlight key differences from the frequency-degenerate case, showing that an adapted theoretical analysis is essential to avoid significant misestimations and to reliably certify entanglement.