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Multi-dimensional entangled states have been proven to be more powerful in some quantum information process. In this paper, down-converted photons from spontaneous parametric down conversion(SPDC) are used to engineer multi-dimensional…

Quantum Physics · Physics 2015-06-26 Xi-Feng Ren , Guo-Ping Guo , Jian Li , Chuan-Feng Li , Guang-Can Guo

We have experimentally implemented the distribution of photon pairs produced by spontaneous parametric down conversion through telecom dense wavelength division multiplexing filters. Using the measured counts and coincidences between…

Quantum Physics · Physics 2015-06-11 Joe Ghalbouni , Imad Agha , Robert Frey , Eleni Diamanti , Isabelle Zaquine

Using the process of spontaneous parametric down conversion in a novel two-crystal geometry, one can generate a source of polarization-entangled photon pairs which is orders of magnitude brighter than previous sources. We have measured a…

Quantum Physics · Physics 2009-10-31 Paul G. Kwiat , Edo Waks , Andrew G. White , Ian Appelbaum , Philippe H. Eberhard

We propose two schemes to generate four-photon polarization-entangled states from the second-order emission of the spontaneous parametric down-conversion process. By using linear optical elements and the coincidence-detection, the four…

Quantum Physics · Physics 2020-08-04 Dong Ding , Yingqiu He , Fengli Yan , Ting Gao

It was shown recently that entanglement of identical particles has a feature called dualism [Phys. Rev. Lett. 110, 140404 (2013)], which is fundamentally connected with quantum indistinguishability. Here we report an experiment that…

Quantum Physics · Physics 2016-11-18 J. -J. Ma , X. -X. Yuan , C. Zu , X. -Y. Chang , P. -Y. Hou , L. -M. Duan

The dependence of one- and two-photon characteristics of pulsed entangled two-photon fields generated in spontaneous parametric down-conversion on the pump-pulse properties (shape of the pump-pulse spectrum and its internal structure) is…

Quantum Physics · Physics 2009-10-31 Jan Perina

It is found that the differential cross section of photon-photon scattering is a function of the degree of polarization entanglement of the two-photon state. A reduced, general expression for the differential cross section of photon-photon…

Quantum Physics · Physics 2017-01-11 Dennis Rätzel , Martin Wilkens , Ralf Menzel

We present a novel yet simple approach to produced multiple entangled photon pairs through spontaneous parametric downconversion. We have developed Gaussian masks to subdivide the pump beam before passing it through a nonlinear medium. In…

Quantum Physics · Physics 2021-05-13 Phillip Heitert , Finn Buldt , Pascal Bassene , Moussa N'Gom

The covariant quantization of the electromagnetic field in the Lorentz gauge gives rise to longitudinal and scalar photons in addition to the usual transverse photons. It is shown here that the exchange of longitudinal and scalar photons…

Quantum Physics · Physics 2015-05-30 J. D. Franson

The generation of pulsed polarization entangled photon pair has been realized using type-I phase matching in the spontaneous parametirc downconversion process in a space cascaded two-crystal geometry. The optical axes of the crystal are…

Quantum Physics · Physics 2009-11-07 Bao-Sen Shi , Akihisa Tomita

We report the observation of an optical vortex in the correlations of photons produced from spontaneous parametric down-conversion. The singularity appears in a non-local coordinate plane consisting of one degree of freedom of each photon.

Quantum Physics · Physics 2009-07-24 R. M. Gomes , A. Salles , F. Toscano , P. H. Souto Ribeiro , S. P. Walborn

Over the past decade, Airy beams have been the subject of extensive research, leading to new physical insights and various applications. In this letter, we extend the concept of Airy beams to the quantum domain. We generate entangled…

Optics · Physics 2020-09-18 Ohad Lib , Yaron Bromberg

Quantum entanglement across spatially separated network nodes is conventionally established through the distribution of photons from a common source or via entanglement swapping that relies on Bell-state measurements and pre-shared…

Quantum Physics · Physics 2026-01-06 Sören Arlt , Mario Krenn , Xuemei Gu

Using spontaneous parametric down conversion and a 50:50 beam splitter, we generate coaxial polarization-entangled photon pairs, of which the two photons are far separated from each other. The photons are then sent one by one through one…

Quantum Physics · Physics 2010-05-06 Xian-Min Jin , Cheng-Zhi Peng , Tao Yang , Youjin Deng

The thorough characterization of entangled-photon sources is vital for their optimal use in quantum communication. However, this task is not trivial at telecommunication wavelengths. While cameras and spectrometers are well developed for…

We explore the possibility of detecting entangled photon pairs from cosmic microwave background or other cosmological sources coming from two patches of the sky. The measurements use two detectors with different photon polarizer directions.…

Quantum Physics · Physics 2019-03-05 Jiunn-Wei Chen , Shou-Huang Dai , Debaprasad Maity , Sichun Sun , Yun-Long Zhang

We investigate transverse spatial entanglement between photon pairs of different wavelengths using a camera-based coincidence technique. By adapting the correlation measurements to the photons frequencies, we certify the presence of…

Quantum Physics · Physics 2025-08-20 Emma Brambila , Raphael Guitter , René Sondenheimer , Markus Gräfe , Hugo Defienne

We demonstrate experimentally that it is possible to prepare and detect photon pairs created by spontaneous parametric down-conversion which exhibit simultaneous position-momentum and polarization correlations that are adequate to implement…

Quantum Physics · Physics 2007-05-23 M. P. Almeida , S. P. Walborn , P. H. Souto Ribeiro

Spectrally correlated photon pairs can be used to improve performance of long range fiber based quantum communication protocols. We present a source based on spontaneous parametric down-conversion producing polarization entangled photons…

Optics · Physics 2014-03-28 Thomas Lutz , Piotr Kolenderski , Thomas Jennewein

The time-energy entanglement of down-converted photon pairs is particularly difficult to characterize because direct measurements of photon arrival times are limited by the temporal resolution of photon detection. Here, we explore an…

Quantum Physics · Physics 2013-04-12 Changliang Ren , Holger F. Hofmann