Quantum enhanced non-interferometric quantitative phase imaging

摘要

Quantum entanglement and squeezing have significantly improved phase estimation and imaging in interferometric settings beyond the classical limits.However,for a wide class of non-interferometric phase imaging/retrieval methods vastly used in the classical domain,e.g.,ptychography and diffractive imaging,a demonstration of quantum advantage is still missing.Here,we fill this gap by exploiting entanglement to enhance imaging of a pure phase object in a non-interferometric setting,only measuring the phase effect on the free-propagating field.This method,based on the so-called"transport of intensity equation",is quantitative since it provides the absolute value of the phase without prior knowledge of the object and operates in wide-field mode,so it does not need time-consuming raster scanning.Moreover,it does not require spatial and temporal coherence of the incident light.Besides a general improvement of the image quality at a fixed number of photons irradiated through the object,resulting in better discrimination of small details,we demonstrate a clear reduction of the uncertainty in the quantitative phase estimation.Although we provide an experimental demonstration of a specific scheme in the visible spectrum,this research also paves the way for applications at different wavelengths,e.g.,X-ray imaging,where reducing the photon dose is of utmost importance.