Quantum imaging can beat classical resolution limits, imposed by the diffraction of light. In particular, it is known that one can reduce the image blurring and increase the achievable resolution by illuminating an object by entangled light and measuring coincidences of photons. If an n-photon entangled state is used and the nth-order correlation function is measured, the point-spread function (PSF) effectively becomes n−−√ times narrower relatively to classical coherent imaging. Quite surprisingly, measuring n-photon correlations is not the best choice if an n-photon entangled state is available. We show that for measuring (n − 1)-photon coincidences (thus, ignoring one of the available photons), PSF can be made even narrower. This observation paves a way for a strong conditional resolution enhancement by registering one of the photons outside the imaging area. We analyze the conditions necessary for the resolution increase and propose a practical scheme, suitable for observation and exploitation of the effect.
|Original language||English (US)|
|Journal||npj Quantum Information|
|State||Published - Aug 9 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-08-11
Acknowledgements: All the authors acknowledge financial support from the King Abdullah University of Science and Technology (grant 4264.01), A.B.M., I.L.K., and D.S.M. also acknowledge support from the EU Flagship on Quantum Technologies, project PhoG (820365).