Imaging spatiotemporal Hong-Ou-Mandel interference of biphoton states of extremely high Schmidt number

We report the experimental observation of a spatiotemporal Hong-Ou-Mandel (HOM) interference of biphoton states of extremely high Schmidt number. Two-photon interference of 1500 spatial modes and a total of more than 3 × 10 6 spatiotemporal modes is evidenced by measuring momentum spatial coincidences, without any prior selection of the photons in time and space coincidence, between the pixels of the far-field images of two strongly multimode spontaneous parametric down-conversion (SPDC) beams propagating through a HOM interferometer. The outgoing SPDC beams are recorded on two separate detector arrays operating in the photon-counting regime. The properties of HOM interference are investigated both in the time and space domains. We show that the two-photon interference exhibits temporal and two-dimensional spatial HOM dips with visibilities of 60% and widths in good agreement with the spatiotemporal coherence properties of the biphoton state. Moreover, we demonstrate that maxima of momentum spatial coincidences are evidenced within each image, in correspondence with these dips

Restoring and tailoring very high dimensional spatial entanglement of a biphoton state transmitted through a scattering medium

We report experimental results where a momentum entangled biphoton state with a giant dimensionality of 8000 is retrieved and manipulated when only one photon of the pair is transmitted through a thin scattering medium. For this purpose, the transmission matrix of the complex medium is first measured with a phase-shifting interferometry measurement method using a spatial light modulator (SLM) illuminated with a laser source. From this matrix, different phase masks are calculated and addressed on the SLM to spatially control the focusing of the laser through the complex medium. These same masks are used to manipulate the phase of the biphoton wave function transmitted by the thin diffuser in order to restore and control in the same way the momentum correlations between the far-field images of twin beams issued from strongly spatial-multi-mode spontaneous parametric down conversion.Comment: 5 pages, 4 figure

Étude expérimentale des fluctuations d'origine quantique en amplification paramétrique d'images

This dissertation presents an experimental study of spatial quantum fluctuations of light in optical parametric amplification (OPA). First, we characterize the response of a CCD camera for the measurement of the spatial shot noise in the image transverse plane. We show the high capabilities of silicon arrays for the visible domain (527 nm) contrary to its bad response in the near IR domain (1055 nm). Then, we use a calibration method of the sensitivity of pixels to eliminate inhomogeneities and to retrieve shot noise for high and low intensity levels. Next, we study the quantum aspects of OPA. The best experimental solution is to amplify a shot noise limited image (527 nm) by a UV pump (264 nm) in a type I BBO cristal. We define an experimental scheme and a protocol of measurement to compare the phase sensitive amplification scheme (PSA) and the phase insensitive amplification scheme (PIA). For the PIA case, we show the degradation of the signal to noise ratio. And for the PSA case, we achieved the first spatially noiseless amplification of images. For both cases, experimental values are in good agreement with theoretical noise figure. Moreover, we study the spatial fluctuations of parametric fluorescence. Using short pulses combined with a narrow spectral filter, we directly characterize a pure distribution of Bose-EinsteinCe mémoire présente une étude expérimentale des fluctuations spatiales d'origine quantique de l'intensité dans des images en amplification paramétrique optique (OPA). Dans un premier temps nous avons caractérisé la réponse d'une caméra CCD lors de la mesure du bruit de photons dans le plan transverse de l'image. Pour cela, nous avons montré la pleine aptitude des capteurs silicium pour le domaine visible (527 nm) et leur mauvaise réponse dans le proche IR (1055 nm). Puis nous avons calibré le capteur sur toute sa dynamique afin d'éliminer l'inhomogénéité de réponse des pixels et ainsi mesurer le bruit de photons dans des images faibles ou intenses. D'autre part, nous avons étudié les aspects quantiques des OPA. L'amplification à l'aide d'un cristal de BBO de type I d'images (527 nm) dominées par le bruit quantique à l'aide d'une pompe UV (264nm) s'est imposée comme le meilleur compromis expérimental. Nous avons mis au point un montage et un protocole de mesure permettant la comparaison entre l'amplification sensible à la phase (PSA) et l'amplification insensible à la phase (PIA). Dans le cas d'une PIA, nous avons mis en évidence la dégradation du rapport signal à bruit. Pour la configuration PSA, nous avons réalisé la première amplification paramétrique d'images sans bruit spatial. Pour ces deux cas, les valeurs expérimentales sont en accord avec la figure de bruit attendue. De plus, nous avons étudié la distribution des fluctuations spatiales de la fluorescence paramétrique. L'emploi d'impulsions brèves et un fort filtrage des longueurs d'onde ont permis la caractérisation directe de la distribution de Bose-Einstein pure

Holographie quantique à 2 photons

International audienc

Stochastic numerical simulations of a fully spatiotemporal Hong-Ou-Mandel dip

International audienceWe develop a fully spatiotemporal numerical model, based on stochastic simulations, simulating the generation of spatiotemporal multimode spontaneous parametric down-conversion, the propagation of the signal and idler beams through a Hong-Ou-Mandel (HOM) interferometer, and the detection of the outgoing beams with two separate detectors arrays. Spatial and temporal properties of the two-photon interference are investigated by measuring the spatial distribution of the momentum correlations between the time-integrated outgoing far-field images and a full spatiotemporal HOM dip is exhibited. Numerical results also demonstrate that the spatiotemporal coherence properties of biphoton wave packets can be fully characterized by detectors arrays with no temporal resolution

Quantum coincidence holography

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Entangled photons through thick scattering media: experiments and comparison with simulations of the biphoton wave function

International audienceWe report experimentally and numerically quantum correlations imaging through thick random media. We demonstrated that spatial correlations between twin photon are still detected but no in form of two-photon speckle-like patterns

Holographie quantique avec des biphotons intriqués de grande dimensionalité spatiale

International audienceNous présentons les résultats expérimentaux de la restitution d’un hologramme de phase par la mesure de corrélations quantiques spatiales entre des paires de photons intriqués (biphotons) avec une dimensionnalité spatiale d’environ 1800. Ces biphotons, générés par émission paramétrique spontanée dans un cristal non linéaire, sont transmis à travers un hologramme de phase. Les photons jumeaux sont ensuite détectés en champ lointain séparément sur 2 caméras EMCCD. La restitution de l’information contenue dans l’hologramme de phase est finalement obtenue en mesurant la répartition des coïncidences spatiales d’origine quantique entre les images jumelles