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

International Conference Laser Optics (ICLO)

Influence of polarization deviation in SPDC on the degree of entanglement of photon pairs

Dmitry N. Frolovtsev, D. P. Agapov, Sergey A Magnitskiy

Published Jun 1, 2018• 0 citations
Publisher

Abstract

We analyze the impact of the polarization deviation [1] on the states of polarization-entangled photons produced via a double crystal scheme. The negative influence of polarization deviation is disclosed and characterized, and we propose the method allowing one to fully compensate the negative action of this effect and to achieve maximum degree of entanglement.

DOI
10.1109/lo.2018.8435212

Related papers

A double-crystal scheme with full compensation of the Migdall effect

Dmitry N. Frolovtsev, Sergey A Magnitskiy

The double-crystal scheme for polarization-entangled photon pairs generation is presented. The negative impact of the Migdall effect on the polarization entanglement is fully compensated in the scheme. The theory for quantifying of entanglement decrease as the action of the Migdall effect is formulated.

EPJ Web of Conferences•Jan 1, 2019•4 citations

On the Improvement of the Degree of Polarization Entanglement in the Double-Crystal Scheme of Spontaneous Parametric Down-Conversion

Dmitry N. Frolovtsev, Sergey A Magnitskiy

A method has been proposed to improve the degree of polarization entanglement of biphotons obtained by means of a double-crystal scheme. The effect of deviation of the polarization of spontaneous parametric down-converted radiation on the degree of polarization entanglement of biphotons has been examined theoretically and experimentally. The dependence of the concurrence as a measure of entanglement on the difference between the pump phases in the nonlinear crystals of the double-crystal scheme has been studied experimentally, and the improvement of the concurrence by a factor of 2.7 has been achieved at the optimal phase difference.

Journal of Experimental and Theoretical Physics Letters•Jan 1, 2024•1 citation

SPONTANNOE PARAMETRIChESKOE RASSEYaNIE V DVUOSNYKh NELINEYNO-OPTIChESKIKh KRISTALLAKh: OSOBENNOSTI SOSTOYaNIYa POLYaRIZATsII IZLUChENIYa

Dmitry N. Frolovtsev, Sergey A Magnitskiy

A consistent analysis of the quantum state of polarization of SPDC radiation is presented and the peculiarities of the quantum state of polarization of SPDC in biaxial nonlinear optical crystals are considered. It is shown that the SPDC polarization deviation angle can exceed 15°, and the angle between the signal and idler wave vectors D can exceed 30°. Estimates of the curvature of the cone formed by SPDC radiation in biaxial crystals are also given. The influence of SPDC polarization deviation in a non-collinear mode on the entanglement of biphoton states generated by a double-crystal scheme is analyzed, it is shown that Tangle of the generated quantum state can deteriorate by 6%, and conditions are identified under which entanglement can be completely restored.

Журнал Экспериментальной и Теоретической Физики•Jan 15, 2024•0 citations

Effect of polarization deviation of spontaneous parametric down-conversion on the degree of biphoton entanglement

Dmitry N. Frolovtsev, Sergey A Magnitskiy

Analysis is given to the effect of polarization deviation due to spontaneous parametric downconversion on the states of polarization-entangled photons generated via a cascaded two-crystal geometry with type I phase matching (e−oo).

Physics of Wave Phenomena•Jul 1, 2017•8 citations

Effect of double pair emission to entanglement based QKD

Stefano Bettelli, Thomas Lorünser, Momtchil Peev +7 more

It is well-known that multi-photon signals in quantum key distribution (QKD) with weak laser pulses represent a security threat resulting in a reduced rate for secret-key production. Similarly, multi-pair contributions from spontaneous-parametric-down-conversion (SPDC) sources may cause information leak. In particular, in the case of polarization coding (i.e., when the polarization of photons is used to encode the logical qubits) a security risk occurs when the polarizations show some degree of correlation. In such a case an eavesdropper can perform a photon number splitting (PNS) attack by getting hold of, and analyzing, one photon out of the multi-photon state without causing any disturbance to the polarization of the other ones. It is therefore important to estimate the relative amount of polarization- correlated multi-pairs in SPDC signals. We present and discuss the results of a recent investigation on this subject. In our study, we consider a CW-SPDC-source scheme of Kwiat type, fully based on polarization-entanglement. The down-converted field is produced continuously, and a suitably chosen coincidence window replaces the concept of pulses.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2007•6 citations

Polarization-entangled photon pairs generation via interference of nonorthogonal quantum states

Dmitry N. Frolovtsev, Sergey A Magnitskiy

We report a new method for generation of polarization-entangled photon pairs in maximally entangled polarization states. Our approach is based on quantum interference between two polarization states which are non-orthogonal. We present necessary and sufficient conditions for generation the photon pair in a maximally entangled state. The effect of dependence of entanglement on the phase between the interfering states of photons is investigated theoretically and demonstrated experimentally with quantum states produced via spontaneous parametric down-conversion in the double-crystal scheme.

International Conference Laser Optics (ICLO)•Nov 2, 2020•1 citation
We analyze the impact of the polarization deviation [1] on the states of polarization-entangled photons produced via a double crystal scheme. The negative influence of polarization deviation is disclosed and characterized, and we propose the method allowing one to fully compensate the negative action of this effect and to achieve maximum degree of entanglement.
A method has been proposed to improve the degree of polarization entanglement of biphotons obtained by means of a double-crystal scheme. The effect of deviation of the polarization of spontaneous parametric down-converted radiation on the degree of polarization entanglement of biphotons has been examined theoretically and experimentally. The dependence of the concurrence as a measure of entanglement on the difference between the pump phases in the nonlinear crystals of the double-crystal scheme has been studied experimentally, and the improvement of the concurrence by a factor of 2.7 has been achieved at the optimal phase difference.
A consistent analysis of the quantum state of polarization of SPDC radiation is presented and the peculiarities of the quantum state of polarization of SPDC in biaxial nonlinear optical crystals are considered. It is shown that the SPDC polarization deviation angle can exceed 15°, and the angle between the signal and idler wave vectors D can exceed 30°. Estimates of the curvature of the cone formed by SPDC radiation in biaxial crystals are also given. The influence of SPDC polarization deviation in a non-collinear mode on the entanglement of biphoton states generated by a double-crystal scheme is analyzed, it is shown that Tangle of the generated quantum state can deteriorate by 6%, and conditions are identified under which entanglement can be completely restored.
It is well-known that multi-photon signals in quantum key distribution (QKD) with weak laser pulses represent a security threat resulting in a reduced rate for secret-key production. Similarly, multi-pair contributions from spontaneous-parametric-down-conversion (SPDC) sources may cause information leak. In particular, in the case of polarization coding (i.e., when the polarization of photons is used to encode the logical qubits) a security risk occurs when the polarizations show some degree of correlation. In such a case an eavesdropper can perform a photon number splitting (PNS) attack by getting hold of, and analyzing, one photon out of the multi-photon state without causing any disturbance to the polarization of the other ones. It is therefore important to estimate the relative amount of polarization- correlated multi-pairs in SPDC signals. We present and discuss the results of a recent investigation on this subject. In our study, we consider a CW-SPDC-source scheme of Kwiat type, fully based on polarization-entanglement. The down-converted field is produced continuously, and a suitably chosen coincidence window replaces the concept of pulses.
We report a new method for generation of polarization-entangled photon pairs in maximally entangled polarization states. Our approach is based on quantum interference between two polarization states which are non-orthogonal. We present necessary and sufficient conditions for generation the photon pair in a maximally entangled state. The effect of dependence of entanglement on the phase between the interfering states of photons is investigated theoretically and demonstrated experimentally with quantum states produced via spontaneous parametric down-conversion in the double-crystal scheme.