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Recent advances in techniques for generating quantum light have stimulated research on novel spectroscopic measurements using quantum entangled photons. One such spectroscopy technique utilizes non-classical correlations among entangled…

Chemical Physics · Physics 2021-07-28 Yuta Fujihashi , Akihito Ishizaki

We report a versatile and practical approach for generating high-quality polarization entanglement in a fully guided-wave fashion. Our setup relies on a high-brilliance type-0 waveguide generator producing paired photon at a telecom…

Quantum Physics · Physics 2013-10-31 F. Kaiser , A. Issautier , L. A. Ngah , O. Alibart , A. Martin , S. Tanzilli

Entangled biphoton sources exhibit nonclassical characteristics and have been applied to imaging techniques such as ghost imaging, quantum holography, and quantum optical coherence tomography. The development of wide-field quantum imaging…

Quantum Physics · Physics 2025-07-11 Zhe He , Yide Zhang , Xin Tong , Lei Li , Lihong V. Wang

There are a number of different strategies to measure the phase shift between two pathways of light more efficiently than suggested by the standard quantum limit. One way is to use highly entangled photons. Another way is to expose photons…

Quantum Physics · Physics 2017-06-19 Lewis A. Clark , Adam Stokes , M. Mubashir Khan , Gangcheng Wang , Almut Beige

Accurately controlling the quantum coherence of photons is pivotal for their applications in quantum sensing and quantum imaging. Here, we propose the utilization of quantum entanglement and local phase manipulation techniques to control…

Quantum Physics · Physics 2023-09-19 Dianzhen Cui , Xi-Lin Wang , X. X. Yi , Li-Ping Yang

We put forward and demonstrate experimentally a {\it quantum-inspired} protocol that allows to quantify the degree of similarity between two spatial shapes embedded in two optical beams without the need to measure the amplitude and phase…

Optics · Physics 2022-12-07 Daniel F. Urrego , Juan P. Torres

Using a spontaneous parametric-downconversion source of photon pairs, we are working towards the creation of arbitrary 2-qubit quantum states with high fidelity. Currently, all physically allowable combinations of polarization entanglement…

Quantum Physics · Physics 2007-05-23 Paul Kwiat , Joe Altepeter , David Branning , Evan Jeffrey , Nicholas Peters , Tzu-Chieh Wei

A key goal of quantum communication is to determine the maximum number of bits shared between two quantum systems. An important example of this is in entanglement based quantum key distribution (QKD) schemes. A realistic treatment of this…

Quantum Physics · Physics 2015-06-04 Thomas Brougham , Stephen M. Barnett

Conventional nonlinear spectroscopy uses classical light to detect matter properties through the variation of its response with frequencies or time delays. Quantum light opens up new avenues for spectroscopy by utilizing parameters of the…

Quantum Physics · Physics 2017-02-01 Konstantin E. Dorfman , Frank Schlawin , Shaul Mukamel

The heralded generation of entangled states is a long-standing goal in quantum information processing, because it is indispensable for a number of quantum protocols. Polarization entangled photon pairs are usually generated through…

Quantum entanglement is at the heart of quantum information sciences and quantum technologies. In the optical domain, the most common type of quantum entanglement is polarization entanglement, which is usually created in a postselection…

Quantum Physics · Physics 2021-07-27 Dat Thanh Le , Warit Asavanant , Nguyen Ba An

Optical quantum information processing needs ultra-bright sources of entangled photons, especially from synchronizable femtosecond lasers and low-cost cw-diode lasers. Decoherence due to timing information and spatial mode-dependent phase…

Quantum Physics · Physics 2010-01-26 Radhika Rangarajan , Michael Goggin , Paul Kwiat

The state of a two-particle system is called entangled when its quantum mechanical wave function cannot be factorized in two single-particle wave functions. Entanglement leads to the strongest counter-intuitive feature of quantum mechanics,…

Quantum Physics · Physics 2009-11-07 E. Altewischer , M. P. van Exter , J. P. Woerdman

We describe and experimentally demonstrate a three-party quantum secret sharing protocol using polarization-entangled photon pairs. The source itself serves as an active participant and can switch between the required photon states by…

Quantum Physics · Physics 2019-06-19 Brian P. Williams , Joseph M. Lukens , Nicholas A. Peters , Bing Qi , Warren P. Grice

Particle entanglement is a fundamental resource upon which are based many quantum technologies. However, the up-to-now best sources of entangled photons rely on parametric down-conversion processes, which are optimal only at certain…

Spatially entangled photon pairs (biphotons) generated by spontaneous parametric down-conversion offer unique opportunities for quantum imaging, but image-plane biphoton correlations are difficult to observe with camera-based detectors.…

Quantum Physics · Physics 2026-01-01 David McFadden , Rainer Heintzmann

We consider the quantum field theory for a scalar model of the electromagnetic field interacting with a system of two-level atoms. In this setting, we show that it is possible to uniquely determine the density of atoms from measurements of…

Analysis of PDEs · Mathematics 2026-02-03 Matti Lassas , Medet Nursultanov , Lauri Oksanen , John C. Schotland

Entangled photons can be used to make measurements with an accuracy beyond that possible with classical light. While most implementations of quantum metrology have used states made up of a single colour of photons, we show that entangled…

We experimentally demonstrate polarization entanglement for squeezed vacuum pulses containing more than 10^5 photons. We also study photon-number entanglement by calculating the Schmidt number and measuring its operational counterpart.…

Quantum Physics · Physics 2012-11-16 Timur Sh. Iskhakov , Ivan N. Agafonov , Maria V. Chekhova , Gerd Leuchs

Quantum entanglement among multiple spatially separated particles is of fundamental interest, and can serve as central resources for studies in quantum nonlocality, quantum-to-classical transition, quantum error correction, and quantum…