Grant: Alliance Grants

Quantum imaging leverages quantum correlations to map out the spatial features of an object. At its core, this technique involves capturing the spatial correlations among photons, a process that has shifted from the labor-intensive single-point sequential scanning methods to the more efficient use of single-photon cameras. These cameras allow for the simultaneous measurement of multiple spatial modes, streamlining the process significantly. Such advancements in quantum sensing have paved the way for various applications in quantum information processing, including high-dimensional entanglement imaging and verification, noise-resilient image refinement, quantum holography powered by entanglement, and notably, quantum microscopy through Hong-Ou-Mandel (HOM) interferometry. In HOM interferometry, photons are directed into a beam-splitter and are jointly detected at the splitter's outputs. When identical photons coincide at the splitter's output, they clump together, interfering destructively. This effect has been used to achieve precise surface imaging, with the added benefit that it is robust against mechanical disruptions like vibrations. The main aim of the collaboration is to refine HOM imaging by manipulating the symmetry of the photon states entering the interferometer. HOM interferometry's output varies with the symmetry of the initial state; symmetric states produce to destructive interference, whereas anti-symmetric states result in constructive interference. By engineering entangled states to be either symmetric or anti-symmetric, it is possible to generate a phase-dependent HOM interference pattern. This can significantly boost the system's resolution, allowing for the detection of features as small as a few nanometers.