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We study the processes of spontaneous four wave mixing and of third-order spontaneous parametric downconversion in optical fibers, as the basis for the implementation of photon-pair and photon-triplet sources. We present a comparative…

Quantum Physics · Physics 2013-07-15 Karina Garay-Palmett , Maria Corona , Alfred U'Ren

Using a spontaneous-downconversion photon source, we produce true non-maximally entangled states, i.e., without the need for post-selection. The degree and phase of entanglement are readily tunable, and are characterized both by a standard…

Quantum Physics · Physics 2009-10-31 Andrew G. White , Daniel F. V. James , Philippe H. Eberhard , Paul G. Kwiat

We experimentally demonstrate the first quantum system entangled in every degree of freedom (hyperentangled). Using pairs of photons produced in spontaneous parametric downconversion, we verify entanglement by observing a Bell-type…

Quantum Physics · Physics 2009-05-15 Julio T. Barreiro , Nathan K. Langford , Nicholas A. Peters , Paul G. Kwiat

We study the process of co-polarized spontaneous four-wave mixing in single-mode optical fibers, with an emphasis on an analysis of the conversion efficiency. We consider both the monochromatic-pumps and pulsed-pumps regimes, as well as…

Quantum Physics · Physics 2015-06-17 Karina Garay-Palmett , Alfred B. U'Ren , Raúl Rangel-Rojo

Entangled photon-pair sources based on spontaneous parametric processes are widely used in photonic quantum information experiments. In this paper, we clarify the relationship between average photon-pair number and the visibility of…

Quantum Physics · Physics 2015-05-13 Hiroki Takesue , Kaoru Shimizu

The cascaded decay in a four-level quantum emitter is a well established mechanism to generate polarization entangled photon pairs, the building blocks of many applications in quantum technologies. The four most prominent maximally…

This work analyses the temporal coherence and correlation of counterpropagating twin photons generated in a quasi-phase matched nonlinear cristal by spontaneous parametric-down conversion. We find out different pictures depending on the…

Quantum Physics · Physics 2017-11-23 Alessandra Gatti , Tommaso Corti , Enrico Brambilla

In virtual-state spectroscopy, information about the energy-level structure of an arbitrary sample is retrieved by Fourier transforming sets of measured two-photon absorption probabilities of entangled photon pairs where the degree of…

Quantum Physics · Physics 2021-08-04 Lutz Mertenskötter , Kurt Busch , Roberto de J. León-Montiel

We investigate in a general form entanglement of biphoton qutrits and ququarts, i.e. states formed in the processes of collinear and, correspondingly, degenerate and non-degenerate Spontaneous Parametric Down-Conversion.…

Quantum Physics · Physics 2010-09-28 Mikhail Fedorov , Peter Volkov , Julia Mikhailova , Stanislav Straupe , Sergei Kulik

High-dimensional entanglement in the form of transverse spatial correlation between a pair of photons generated via spontaneous parametric downconversion is not only a valuable resource in many academic and real-life applications but also…

Quantum Physics · Physics 2025-08-18 Rounak Chatterjee , Vikas S Bhat , Kiran Bajar , Sushil Mujumdar

Entangling microwave and optical photons is one of the promising ways to realize quantum transduction through quantum teleportation. This paper investigates the entanglement of microwave-optical photon pairs generated from an…

Quantum Physics · Physics 2024-07-30 Changchun Zhong , Fangxin Li , Srujan Meesala , Steven Wood , David Lake , Oskar Painter , Liang Jiang

Generation and characterization of entanglement are crucial tasks in quantum information processing. A hypothesis testing scheme for entanglement has been formulated. Three designs were proposed to test the entangled photon states created…

Structured optical fields have led to several ground-breaking techniques in classical imaging and microscopy. At the same time, in the quantum domain, position-momentum entangled photon fields have been shown to have several unique features…

We show that in parametric down-conversion the coherence properties of a temporally partially coherent pump field get entirely transferred to the down-converted entangled two-photon field. Under the assumption that the frequency-bandwidth…

Quantum Physics · Physics 2017-07-24 Girish Kulkarni , Prashant Kumar , Anand K. Jha

We verify transverse spatial entanglement of photon-pairs generated in spontaneous parametric down conversion using a nonlinear interferometric technique without relying on any coincidence detection. We experimentally demonstrate the…

We present an experimental scheme based on spontaneous parametric down-conversion to produce multiple photon pairs in maximally entangled polarization states using an arrangement of two type-I nonlinear crystals. By introducing correlated…

Quantum Physics · Physics 2013-02-01 K. Dobek , M. Karpinski , R. Demkowicz-Dobrzanski , K. Banaszek , P. Horodecki

We employ a cascaded system approach to numerically simulate the interaction of photon pulses with a two-level scatterer in a chiral waveguide QED setup. It is possible to expand any pure state of two photons as a superposition of…

Quantum Physics · Physics 2022-09-27 Mads Middelhede Lund , Fan Yang , Klaus Mølmer

The complete measurement of the quantum state of two correlated photons requires reconstructing the amplitude and phase of the biphoton wavefunction. We show how, by means of spatially resolved single photon detection, one can infer the…

Quantum Physics · Physics 2025-06-26 Nazanin Dehghan , Alessio D'Errico , Francesco Di Colandrea , Ebrahim Karimi

The question of whether entanglement between photons is equivalent to entanglement between their characteristic field modes, specifically, the single-particle wavefunctions that are composed and superposed to describe particles in such…

Quantum Physics · Physics 2026-03-10 Aniruddha Bhattacharya

In this work the degree of entanglement of two-photon states generated by parametric-down conversion with a phase mismatch is computed in terms of the temperature of the nonlinear medium where the interaction takes place. The minimum…

Quantum Physics · Physics 2012-10-02 Ana M. Martins