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ENCODING and decoding images
ENCODING AND DECODING IMAGES IN QUANTUM OPTICAL CORRELATIONS
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Chloé VERNIÈRE 1, Baptiste COURME 1, 2, Hugo DEFIENNE 1, *
1
Sorbonne Université, CNRS, Institut des NanoSciences de Paris, INSP, F-75005 Paris
2
Laboratoire Kastler Brossel, ENS-Universite PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France * hugo. defienne @ insp. upmc. fr
Quantum correlations, such as those existing between photons produced by spontaneous parametric downconversion( SPDC), are ubiquitous in quantum photonic technologies. To develop applications, they must be precisely tailored and efficiently measured, which is often challenging in practice. This article presents an image encoding-decoding method based on the quantum correlations of photon pairs, highlighting recent advances in detecting and controlling these correlations for imaging and sensing applications. https:// doi. org / 10.1051 / photon / 202513142
This is an Open Access article distributed under the terms of the Creative Commons Attribution License( https:// creativecommons. org / licenses / by / 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Quantum imaging exploits non-classical optical properties to surpass the performance of classical systems or to develop new imaging modalities [ 1 ]. Building on quantum metrology and sensing, this field has developed over the past 40 years. Advances in detector and source technologies, combined with conceptual progress in quantum phenomena such as entanglement and non-locality, have gradually paved the way for practical applications. Notably, the past five years have seen the first proof-of-principle demonstrations of quantum microscopes employing squeezed light [ 2 ], single-photon emitters [ 3 ] and entangled photons [ 4 ].
Among quantum imaging techniques, many leverage photon correlations to enhance imaging performance. Photon correlations in so-called‘ twin beams’ were first observed in 1970 in light emitted from χ( 2) nonlinear crystals [ 5 ]. Since then, this nonlinear optical process, known as spontaneous parametric down-conversion( SPDC) [ 6 ], has been extensively studied. Today, it underpins most non-classical light sources used in modern experiments and applications, particularly those that produce entangled photon pairs.
SPONTANEOUS PARAMETRIC DOWN CONVERSION SPDC is a non-linear process in which a photon from a high-energy( e. g. blue) pump laser is converted into two lower-energy( e. g. infrared) photons called signal and idler( Fig. 1a). It is a very inefficient process, as most of the pump photons pass through the crystal unperturbed, with only a small portion( 10 −5 to 10 −12) producing a pair of down-converted photons. When operating in the low gain regime, for example by using a
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