RESUMO
Adaptive optics (AO) has revolutionized imaging in fields from astronomy to microscopy by correcting optical aberrations. In label-free microscopes, however, conventional AO faces limitations because of the absence of a guide star and the need to select an optimization metric specific to the sample and imaging process. Here, we propose an AO approach leveraging correlations between entangled photons to directly correct the point spread function. This guide star-free method is independent of the specimen and imaging modality. We demonstrate the imaging of biological samples in the presence of aberrations using a bright-field imaging setup operating with a source of spatially entangled photon pairs. Our approach performs better than conventional AO in correcting specific aberrations, particularly those involving substantial defocus. Our work improves AO for label-free microscopy and could play a major role in the development of quantum microscopes.
RESUMO
High-dimensional entanglement is a promising resource for quantum technologies. Being able to certify it for any quantum state is essential. However, to date, experimental entanglement certification methods are imperfect and leave some loopholes open. Using a single-photon-sensitive time-stamping camera, we quantify high-dimensional spatial entanglement by collecting all output modes and without background subtraction, two critical steps on the route toward assumptions-free entanglement certification. We show position-momentum Einstein-Podolsky-Rosen (EPR) correlations and quantify the entanglement of formation of our source to be larger than 2.8 along both transverse spatial axes, indicating a dimension higher than 14. Our work overcomes important challenges in photonic entanglement quantification and paves the way toward the development of practical quantum information processing protocols based on high-dimensional entanglement.