Propagation of transverse intensity correlations of a two-photon state (original) (raw)
Related papers
Full-mode characterization of correlated photon pairs generated in spontaneous downconversion
Optics letters, 2021
Spontaneous parametric downconversion is the primary source to generate entangled photon pairs in quantum photonics laboratories. Depending on the experimental design, the generated photon pairs can be correlated in the frequency spectrum, polarization, position-momentum, and spatial modes. Exploring the spatial modes' correlation has hitherto been limited to the polar coordinates' azimuthal angle, and a few attempts to study Walsh mode's radial states. Here, we study the full-mode correlation, on a Laguerre-Gauss basis, between photon pairs generated in a type-I crystal. Furthermore, we explore the effect of a structured pump beam possessing different spatial modes onto bi-photon spatial correlation. Finally, we use the capability to project over arbitrary spatial mode superpositions to perform the bi-photon state's full quantum tomography in a 16-dimensional subspace.
Quantum correlations in optics
Pramana, 1998
In many nonlinear optical problems, for example in down-conversion and four-wave mixing, the photons are generated in pairs. The strong correlation between the photons in a pair, characterized by either the correlations between operators corresponding to observables associated with individual photons, or the correlated state describing the two photons, may lead to various nonclassicalities. We discuss some of these nonclassical effects and their experimental demonstrations in nonlinear optical processes.
Applied Optics, 1995
Recently, optical interpretations of the fractional-Fourier-transform operator have been introduced. On the basis of this operator the fractional correlation operator is defined in two different ways that are both consistent with the definition of conventional correlation. Fractional correlation is not always a shift-invariant operation. This property leads to some new applications for fractional correlation as shift-variant image detection. A bulk-optics implementation of fractional correlation is suggested and demonstrated with computer simulations.
Finite-mode analysis by means of intensity information in fractional optical systems
Journal of the Optical Society of America A, 2002
It is shown how a coherent optical signal that contains only a finite number of Hermite-Gauss modes can be reconstructed from the knowledge of its Radon-Wigner transform-associated with the intensity distribution in a fractional-Fourier-transform optical system-at only two transversal points. The proposed method can be generalized to any fractional system whose generator transform has a complete orthogonal set of eigenfunctions.
2021
The measurement of the position-momentum EPR correlations of a two-photon state is important for many quantum information applications ranging from quantum key distribution to coincidence imaging. However, all the existing techniques for measuring the position-momentum EPR correlations involve coincidence detection and thus suffer from issues that result in less accurate measurements. In this letter, we propose and demonstrate an experimental scheme that does not require coincidence detection for measuring the EPR correlations. Our technique works for two-photon states that are pure, irrespective of whether the state is separable or entangled. We theoretically show that if the pure two-photon state satisfies a certain set of conditions then the position-momentum EPR correlations can be obtained by doing the intensity measurements on only one of the photons. We experimentally demonstrate this technique for pure two-photon states produced by type-I spontaneous parametric down-conversi...
Optics Express, 1998
A single-photon-sensitive intensified charge-coupled-device (ICCD) camera has been used to simultaneously detect, over a broad area, degenerate and nondegenerate photon pairs generated by the quantum-optical process of spontaneous parametric down-conversion. We have developed a new method for determining the quantum fourthorder correlations in spatially extended detection systems such as this one. Our technique reveals the expected phase-matching-induced spatial correlations in a 2-f Fourier-transform system.
Deterministic quantum correlation between coherently paired photons acting on a beam splitter
2021
Quantum technologies based on the particle nature of a photon has been progressed over the last several decades, where the fundamental quantum features of entanglement have been tested by Hong-Ou-Mandeltype anticorrelation and Bell-type nonlocal correlation. Recently, mutually exclusive quantum features based on the wave nature of a photon have been investigated to understand the fundamental physics of ‘mysterious’ quantum correlation, resulting in deterministic and macroscopic quantum technologies. Here, we study the quantum natures of paired photons acting on a beam splitter, where mutual coherence plays a major role. Unlike current common understanding on anticorrelation, bipartite entanglement between paired photons does not have to be probabilistic or post-selected, but can be deterministic and even macroscopic via phase basis manipulation without violating quantum mechanics. Introduction A corpuscular nature of light has been accepted since the photoelectric effect was observe...
The Quantum Features of Correlated Photons with the Effect of Phase Fluctuation
Ukrainian Journal of Physics
We theoretically investigate the effect of phase fluctuations on correlated photons resulting from nondegenerate three-level atoms under the cavity radiation. The photon statistics, photon number correlation, and entanglement properties of the system have been calculated employing the dynamical equation of the system. It is shown that, for the sub-Poissonian photon statistics, the degree of correlation increases with the atomic pumping rate, and the entanglement varies with phase fluctuations, rather than with the atomic pumping rate. The proposed system is well suitable for the quantum information processing.
Dispersion spreading of polarization-entangled states of light and two-photon interference
2007
We study the interference structure of the second-order intensity correlation function for polarizationentangled two-photon light obtained from type-II collinear frequency-degenerate spontaneous parametric down-conversion (SPDC). The structure is visualised due to the spreading of the two-photon amplitude as two-photon light propagates through optical fibre with group-velocity dispersion (GVD). Because of the spreading, polarization-entangled Bell states can be obtained without any birefringence compensation at the output of the nonlinear crystal; instead, proper time selection of the intensity correlation function is required. A birefringent material inserted at the output of the nonlinear crystal (either reducing the initial o-e delay between the oppositely polarized twin photons or increasing this delay) leads to a more complicated interference structure of the correlation function.
Physical Review A, 2008
What are the orbital angular momentum correlations between spatially entangled photon pairs generated in spontaneous parametric down-conversion? We show that the answer to this question can be given in two alternative, although complementary, ways. The answer posed in this letter explains satisfactorily the seemingly contradictory results obtained in different experiments, and theoretical approaches. PACS numbers: 03.67.Mn, 42.50.Dv, 42.65.Lm Within the paraxial quantum optics regime, the orbital angular momentum (OAM) provides an useful description of the spatial degree of freedom of photons. Photons whose spatial waveform contains an azimuthal phase dependence of the form ∼ exp (imϕ), carry an OAM of m per photon . Photons with diverse spatial waveforms can be easily generated, detected, and controlled. Therefore, the OAM offers a physical resource where to explore deeper quantum features not present in the 2dimensional Hilbert space addressed when using the polarization . Indeed, it allows to readily tailor the number of effective dimensions of the Hilbert space .