Speaker: Giacomo Sorelli (Fraunhofer Institute for Optotronics, System Technology and Image Exploitation)

Abstract

Quantum optical metrology aims to identify ultimate sensitivity bounds for the estimation of parameters encoded into quantum states of the electromagnetic field. In many practical applications, including imaging, microscopy, and remote sensing, the parameter of interest is not only encoded in the quantum state of the field, but also in its spatio-temporal distribution, i.e. in its mode structure. In this mode-encoded parameter estimation setting, we derive an analytical expression for the quantum Fisher information valid for arbitrary multimode Gaussian fields. To illustrate the power of our approach, we apply it to the transverse localisation of a Gaussian beam, and to the temporal separation between two pulses. In both cases, we will show which are the relevant modes where to deploy quantum resources, i.e. squeezing, to achieve a sensitivity enhancement.