We investigate the localization of two incoherent point sources with arbitrary angular and axial separations in the paraxial approximation. By using quantum metrology techniques, we show that a simultaneous estimation of the two separations is achievable by a single quantum measurement, with a precision saturating the ultimate limit stemming from the quantum Cramér-Rao bound. Such a precision is not degraded in the sub-wavelength regime, thus overcoming the traditional limitations of classical direct imaging derived from Rayleigh's criterion. Our results are qualitatively independent of the point spread function of the imaging system, and quantitatively illustrated in detail for the Gaussian instance. This analysis may have relevant applications in three-dimensional surface measurements. [Phys. Rev. Lett. 122, 140505 (2019)]

报告人简介：Dr. Samanta Piano is an Assistant Professor at the University of Nottingham. Her current research interest concerns the development of innovative and unconventional optical techniques and 3D probing systems for high-precision coordinate metrology to be used in industrial applications. Samanta received her PhD in Physics in 2007. And her  career in Nottingham has been supported by a Marie Curie Intra-European Fellowship (2009-2011) and a Nottingham Advance Research Fellowship. She has published in international peer reviewed journals (attracting about 500 citations; source: Scopus), including three in the prestigious Physical Review Letters, one in Applied Physics Letters, and three refereed book chapters. She is currently working on novel optical measurement techniques, complex mechanism error modelling and close range photogrammetry. She has recently awarded a Hermes Fellowship to work on application of machine-learning and CAD model recognition techniques to accelerate and optimise the performance of the photogrammetry system.