Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Entanglement analysis and experimental proposal for measuring Bell-type correlations in an injected optical parametric oscillator with structured light

L. G. S. Oliveira, L. J. Pereira, R. M. Pereira, G. B. Alves, J. A. O. Huguenin, Antonio Zelaquett Khoury, K. Dechoum, C. E. R. Souza

Published Apr 1, 2024• 2 citations
Publisher

Abstract

We study a type-II optical parametric oscillator under injection of laser beams with first-order Hermite-Gauss modes. We develop the equations describing the dynamics of this system in the Wigner representation of the density matrix. These equations are solved numerically and compared with the analytical solution in the nondepletion regime. We show that, when the injected beams are much less intense than the pumping beam, the system still exhibits quantum entanglement, which can be witnessed via Duan-Simon criterion and Bell inequalities. We also propose an experimental apparatus for measuring Bell inequalities. This system can generate spin-orbit hyperentangled states, and is thus a useful resource to quantum technology applications and fundamental physics.

DOI
10.1103/physreva.109.043701

Related papers

Active locking and entanglement in type II optical parametric oscillators

J. Ruiz-Rivas, Germán J. de Valcárcel, Carlos Navarrete–Benlloch

Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.

arXiv:1609.07397•New Journal of Physics•Dec 21, 2017•0 citations

Active locking and entanglement in type II optical parametric oscillators

J. Ruiz-Rivas, Germán J. de Valcárcel, Carlos Navarrete–Benlloch

Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.

•Jan 1, 2018•2 citations

Quantum analysis of the nondegenerate optical parametric oscillator with injected signal

B. Coutinho dos Santos, K. Dechoum, Antonio Zelaquett Khoury +2 more

In this paper we study the nondegenerate optical parametric oscillator with injected signal, both analytically and numerically. We develop a perturbation approach which allows us to find approximate analytical solutions, starting from the full equations of motion in the positive-$P$ representation. We demonstrate the regimes of validity of our approximations via comparison with the full stochastic results. We find that, with reasonably low levels of injected signal, the system allows for demonstrations of quantum entanglement and the Einstein-Podolsky-Rosen paradox. In contrast to the normal optical parametric oscillator operating below threshold, these features are demonstrated with relatively intense fields.

arXiv:quant-ph/0507123•Physical Review A•Sep 22, 2005•33 citations

Time-modulated type-II optical parametric oscillator: Quantum dynamics and strong Einstein-Podolsky-Rosen entanglement

Hayk H. Adamyan, Gagik Yu. Kryuchkyan

We investigate semiclassical dynamics and quantum properties of light beams generated in time-modulated nondegenerate optical parametric oscillator (NOPO). Having in view production of continuous-variable (CV) entangled states of light beams we propose two experimentally feasible schemes of NOPO: (i) driven by continuously modulated pump field; (ii) under action of a periodic sequence of identical laser pulses. It is shown that the time modulation of pump field amplitude essentially improves the degree of CV entanglement in NOPO. On the whole the level of integral two-mode squeezing, which characterizes the degree of CV entanglement, goes below the standard limit established in an ordinary NOPO with monochromatic pumping. We develop semiclassical and quantum theories of these devices for both below- and above-threshold regimes of generation. Properties of CV entanglement for various operational regimes of the devices are discussed in the time domain in application to time-resolved quantum information technologies. Our analytical results are in well agreement with the results of numerical simulation and support a concept of CV entangled states of time-modulated light beams.

Physical Review A•Aug 15, 2006•32 citations

Experimental Generation of Continuous-Variable Hyperentanglement in an Optical Parametric Oscillator

Kui Liu, Jun Guo, Chunxiao Cai +2 more

We report on the generation of continuous-variable hyperentanglement of polarization and orbital angular momentum with a type II optical parametric oscillator. By compensating for the astigmatism between spatial modes, we produce an entangled pair of Hermite-Gauss beams. From correlations measurements, we verify the existence of continuous-variable hyperentanglement by the general entanglement criterion as well as by the continuous-variable version of the Peres-Horodecki criterion visualized on an equivalent Poincaré sphere.

Physical Review Letters•Oct 20, 2014•75 citations

The Test of Entanglement of Polarization States of a Semi-Classical Optical Parametric Oscillator

Gerald Mugaya Lisamadi

We study the dynamical continuous variable entanglement in a semi-classical Optical parametric oscillator (OPO). The general time evolving photon polarization state vectors arising from exact analytical solutions of Heisenberg’s equations of the system are used to obtain the photon polarization Bell state vectors. The reduced density matrices of photon polarization Bell state vectors of the semi-classical OPO produce a greater violation of CHSH Bell’s inequality beyond the Cirel’son’s inequality.

American Journal of Modern Physics•Jan 1, 2017•0 citations
We study a type-II optical parametric oscillator under injection of laser beams with first-order Hermite-Gauss modes. We develop the equations describing the dynamics of this system in the Wigner representation of the density matrix. These equations are solved numerically and compared with the analytical solution in the nondepletion regime. We show that, when the injected beams are much less intense than the pumping beam, the system still exhibits quantum entanglement, which can be witnessed via Duan-Simon criterion and Bell inequalities. We also propose an experimental apparatus for measuring Bell inequalities. This system can generate spin-orbit hyperentangled states, and is thus a useful resource to quantum technology applications and fundamental physics.
Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.
Type II optical parametric oscillators are amongst the highest-quality sources of quantum-correlated light. In particular, when pumped above threshold, such devices generate a pair of bright orthogonally-polarized beams with strong continuous-variable entanglement. However, these sources are of limited practical use, because the entangled beams emerge with different frequencies and a diffusing phase difference. It has been proven that the use of an internal wave-plate coupling the modes with orthogonal polarization is capable of locking the frequencies of the emerging beams to half the pump frequency, as well as reducing the phase-difference diffusion, at the expense of reducing the entanglement levels. In this work we characterize theoretically an alternative locking mechanism: the injection of a laser at half the pump frequency. Apart from being less invasive, this method should allow for an easier real-time experimental control. We show that such an injection is capable of generating the desired phase locking between the emerging beams, while still allowing for large levels of entanglement. Moreover, we find an additional region of the parameter space (at relatively large injections) where a mode with well defined polarization is in a highly amplitude-squeezed state.
In this paper we study the nondegenerate optical parametric oscillator with injected signal, both analytically and numerically. We develop a perturbation approach which allows us to find approximate analytical solutions, starting from the full equations of motion in the positive-PPP representation. We demonstrate the regimes of validity of our approximations via comparison with the full stochastic results. We find that, with reasonably low levels of injected signal, the system allows for demonstrations of quantum entanglement and the Einstein-Podolsky-Rosen paradox. In contrast to the normal optical parametric oscillator operating below threshold, these features are demonstrated with relatively intense fields.
We investigate semiclassical dynamics and quantum properties of light beams generated in time-modulated nondegenerate optical parametric oscillator (NOPO). Having in view production of continuous-variable (CV) entangled states of light beams we propose two experimentally feasible schemes of NOPO: (i) driven by continuously modulated pump field; (ii) under action of a periodic sequence of identical laser pulses. It is shown that the time modulation of pump field amplitude essentially improves the degree of CV entanglement in NOPO. On the whole the level of integral two-mode squeezing, which characterizes the degree of CV entanglement, goes below the standard limit established in an ordinary NOPO with monochromatic pumping. We develop semiclassical and quantum theories of these devices for both below- and above-threshold regimes of generation. Properties of CV entanglement for various operational regimes of the devices are discussed in the time domain in application to time-resolved quantum information technologies. Our analytical results are in well agreement with the results of numerical simulation and support a concept of CV entangled states of time-modulated light beams.
We report on the generation of continuous-variable hyperentanglement of polarization and orbital angular momentum with a type II optical parametric oscillator. By compensating for the astigmatism between spatial modes, we produce an entangled pair of Hermite-Gauss beams. From correlations measurements, we verify the existence of continuous-variable hyperentanglement by the general entanglement criterion as well as by the continuous-variable version of the Peres-Horodecki criterion visualized on an equivalent Poincaré sphere.
We study the dynamical continuous variable entanglement in a semi-classical Optical parametric oscillator (OPO). The general time evolving photon polarization state vectors arising from exact analytical solutions of Heisenberg’s equations of the system are used to obtain the photon polarization Bell state vectors. The reduced density matrices of photon polarization Bell state vectors of the semi-classical OPO produce a greater violation of CHSH Bell’s inequality beyond the Cirel’son’s inequality.