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

Measurement Techniques

Measurement Method of the Polarization-Entangled States of Biphotons Using a Quantum Tomograph

Dmitry N. Frolovtsev, Sergey A. Magnitskii, Andrey V. Demin

Published Jan 1, 2022• 2 citations
Publisher
DOI
10.1007/s11018-022-02008-5

Related papers

The measurement method of the polarization-entangled states of biphotons using a quantum tomograph

Dmitry N. Frolovtsev, Sergey A Magnitskiy, Andrey V. Demin

Izmeritel`naya Tekhnika•Jan 1, 2021•0 citations

Quantum Tomograph for Measurement and Characterization of Quantum States of Biphoton Sources

Dmitry N. Frolovtsev, Sergey A Magnitskiy, Andrey V. Demin

Measurement Techniques•Jul 1, 2020•7 citations

Quantum tomograph for measurement and characterization of quantum states of biphoton sources

Dmitry N. Frolovtsev, Sergey A Magnitskiy, Andrey V. Demin

The method and prototype of a device for characterizing of biphoton light sources based on spontaneous parametric downdonversion by quantum tomography are described. The prototype is an experimental implementation of a specialized quantum tomograph designed to measure the quantum polarization states of radiation generated by biphoton sources. Specially developed software will determine the statistical characteristics of the measured quantum state, calculate the tomographic and likelihood estimations of the density matrix, calculate the measurement errors of the density matrix elements and evaluate the quality of the quantum state of biphotons.

Izmeritel`naya Tekhnika•Apr 1, 2020•1 citation

Frequency-induced phase-tunable polarization-entangled narrowband biphotons

Peng Chen, Xianxin Guo, Chi Shu +2 more

Manipulating polarization entanglement of paired photons is always of great interest for understanding the quantum nature of photons and exploring their applications in quantum information processing and quantum communication. Narrowband biphotons with polarization entanglement are especially important for a quantum network based on efficient photon–atom interactions. In most demonstrated cases, the polarization-entangled states are manipulated through the birefringent effect. In this Letter, we produce narrowband polarization-entangled biphotons from spontaneous four-wave mixing in cold atoms and demonstrate a new method to tune the phase of the polarization entanglement by varying the frequency of one of the classical driving lasers. This is achieved through two-photon interference with a path-exchange symmetry. Our result represents a precision control of polarization entanglement from the frequency domain, and may have promising applications in quantum information and precision measurement.

Optica•May 14, 2015•10 citations

Polarization States of Light and Their Quantum Tomography

V. P. Karassiov

Journal of Russian Laser Research•Nov 1, 2005•22 citations

Photon entanglement detection by a single atom

Jan Huwer, Joyee Ghosh, Nicolás Piro +3 more

We use a single trapped 40 Ca + ion as a resonant, polarization-sensitive absorber to detect and characterize the entanglement of tunable narrowband photon pairs from a spontaneous parametric down-conversion source. Single-photon absorption is marked by a quantum jump in the ion and heralded by coincident detection of the partner photon. For three polarization basis settings of the absorption and detection of the herald, we find maximum coincidences always for orthogonal polarizations. The polarization entanglement is further evidenced by tomographic reconstruction of the biphoton quantum state with an overlap fidelity of 93% with the Bell singlet state. This is an essential step toward a single-ion based quantum memory for photonic entanglement.

arXiv:1111.1085•New Journal of Physics•Feb 25, 2013•20 citations
The method and prototype of a device for characterizing of biphoton light sources based on spontaneous parametric downdonversion by quantum tomography are described. The prototype is an experimental implementation of a specialized quantum tomograph designed to measure the quantum polarization states of radiation generated by biphoton sources. Specially developed software will determine the statistical characteristics of the measured quantum state, calculate the tomographic and likelihood estimations of the density matrix, calculate the measurement errors of the density matrix elements and evaluate the quality of the quantum state of biphotons.
Manipulating polarization entanglement of paired photons is always of great interest for understanding the quantum nature of photons and exploring their applications in quantum information processing and quantum communication. Narrowband biphotons with polarization entanglement are especially important for a quantum network based on efficient photon–atom interactions. In most demonstrated cases, the polarization-entangled states are manipulated through the birefringent effect. In this Letter, we produce narrowband polarization-entangled biphotons from spontaneous four-wave mixing in cold atoms and demonstrate a new method to tune the phase of the polarization entanglement by varying the frequency of one of the classical driving lasers. This is achieved through two-photon interference with a path-exchange symmetry. Our result represents a precision control of polarization entanglement from the frequency domain, and may have promising applications in quantum information and precision measurement.
We use a single trapped 40 Ca + ion as a resonant, polarization-sensitive absorber to detect and characterize the entanglement of tunable narrowband photon pairs from a spontaneous parametric down-conversion source. Single-photon absorption is marked by a quantum jump in the ion and heralded by coincident detection of the partner photon. For three polarization basis settings of the absorption and detection of the herald, we find maximum coincidences always for orthogonal polarizations. The polarization entanglement is further evidenced by tomographic reconstruction of the biphoton quantum state with an overlap fidelity of 93% with the Bell singlet state. This is an essential step toward a single-ion based quantum memory for photonic entanglement.