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

Two-photon entanglement in type-II parametric down-conversion

Yanhua H. Shih, Alexander V. Sergienko, Morton H. Rubin, Thomas E. Kiess, C. O. Alley

Published Jul 1, 1994• 91 citations
Publisher

Abstract

We present an experimental study of the entangled two-photon polarization states in type-II optical parametric down-conversion. It is interesting to see that the polarization entanglement depends on the detection spectral bandwidth, i.e., the bandwidth of the spectral filters placed in front of the detectors. The entanglement is also dependent on the length of the down-conversion crystal. A simple quantum model is provided to explain these phenomena.

DOI
10.1103/physreva.50.23

Related papers

Pump Spectral Bandwidth, Birefringence, and Entanglement in Type‐II Parametric Down Conversion

Daniel B. Erenso

The twin photons produced by a type‐II spontaneous parametric down conversion are well know as a potential source of photons for quantum teleportation due to the strong entanglement in polarization. This strong entanglement in polarization, however, depends on the spectral composition of the pump photon and the nature of optical isotropy of the crystal. By exact numerical calculation of the concurrence, we have shown that how pump photons spectral width and the birefringence nature of the crystal directly affect the degree of polarization entanglement of the twin photons.

International Journal of Optics•Jan 1, 2009•2 citations

Quantum correlation of polarization of two-photon entangled state in type-II spontaneous parametric downconversion

Alexander V. Sergienko, Thomas E. Kiess, Y. H. Shih +2 more

Polarization correlation measurement of two-photon state generated in type-II spontaneous parametric downconversion (SPDC) has been performed in a single input port beam splitter configuration. Two orthogonally polarized entangled photons with degenerate k vectors were directed to the single input port 50%-50% beam splitter. Polarization were measured with linear and circular polarization entangled state by the use of two polarization analyzers followed by two photon counting detectors. A strong correlation of polarization has been observed. The type of two-photon state generated in Type-II SPDC was tested. A strong dependence of the polarization correlation upon the spectral bandwidth of the detector spectral filter was found and a different correlation between linear and circular polarization entangled state were observed. It seems that the standard theoretical models for SPDC need to be improved in order to provide a comprehensive treatment for the result of the experiment.

Annual Meeting Optical Society of America•Jan 1, 1993•0 citations

Two-Photon Interference with the Type II Spontaneous Parametric Down-Conversion

Yun-Kun Jiang, Bao-Sen Shi, Jian Li +3 more

The two-photon polarized entangled state is generated from the type II spontaneous parametric down-conversion pumped by a femtosecond pulse. The two-photon interference is observed in the Hong-Ou-Mandel interferometer. The high visibility of the interference is restored with narrow band interference filters placed in front of the detectors. PACS: 42. 50. Dv, 03. 67. -a, 42. 65. Re

Chinese Physics Letters•Dec 13, 2000•6 citations

Theory of two-photon entanglement in type-II optical parametric down-conversion

Morton H. Rubin, Давид Николаевич Клышко, Yanhua H. Shih +1 more

The theory of the two-photon state generated by type-II optical parametric down-conversion is studied with emphasis on the space-time and polarization entanglement of the photons. Several experiments are reviewed that demonstrate various aspects of the quantum nature of this state. The theory of a different type of two-photon interferometer is presented.

Physical Review A•Dec 1, 1994•478 citations

Joint spectrum mapping of polarization entanglement in spontaneous parametric down-conversion

Hou Shun Poh, Chune Yang Lum, I. Marcikic +2 more

Polarization-entangled photon pairs can be efficiently prepared into pure Bell states with a high fidelity via type-II spontaneous parametric down-conversion (SPDC) of narrow-band pump light. However, the use of femtosecond pump pulses to generate multiphoton states with precise timing often requires spectral filtering to maintain a high quality of polarization entanglement. This typically reduces the efficiency of photon pair collection. We experimentally map the polarization correlations of photon pairs from such a source over a range of down-converted wavelengths with a high spectral resolution and find strong polarization correlations everywhere. A spectrally dependent imbalance between contributions from the two possible decay paths of SPDC is identified as the reason for a reduction in entanglement quality observed with femtosecond pump pulses. Our spectral measurements allow us to predict the polarization correlations for arbitrary filter profiles when the frequency degree of freedom of the photon pairs is ignored.

arXiv:quant-ph/0608009•Physical Review A•Apr 26, 2007•47 citations

Broadband source of polarization entangled photons

Andrew M. Fraine, Olga V. Minaeva, David S. Simon +2 more

A broadband source of polarization entangled photons based on type-II spontaneous parametric down conversion from a chirped PPKTP crystal is presented. With numerical simulation and experimental evaluation, we report a source of broadband polarization entangled states with a bandwidth of approximately 125 nm for use in quantum interferometry. The technique has the potential to become a basis for the development of flexible broadband sources with designed spectral properties.

Optics Letters•May 22, 2012•20 citations
We present an experimental study of the entangled two-photon polarization states in type-II optical parametric down-conversion. It is interesting to see that the polarization entanglement depends on the detection spectral bandwidth, i.e., the bandwidth of the spectral filters placed in front of the detectors. The entanglement is also dependent on the length of the down-conversion crystal. A simple quantum model is provided to explain these phenomena.
The twin photons produced by a type‐II spontaneous parametric down conversion are well know as a potential source of photons for quantum teleportation due to the strong entanglement in polarization. This strong entanglement in polarization, however, depends on the spectral composition of the pump photon and the nature of optical isotropy of the crystal. By exact numerical calculation of the concurrence, we have shown that how pump photons spectral width and the birefringence nature of the crystal directly affect the degree of polarization entanglement of the twin photons.
Polarization correlation measurement of two-photon state generated in type-II spontaneous parametric downconversion (SPDC) has been performed in a single input port beam splitter configuration. Two orthogonally polarized entangled photons with degenerate k vectors were directed to the single input port 50%-50% beam splitter. Polarization were measured with linear and circular polarization entangled state by the use of two polarization analyzers followed by two photon counting detectors. A strong correlation of polarization has been observed. The type of two-photon state generated in Type-II SPDC was tested. A strong dependence of the polarization correlation upon the spectral bandwidth of the detector spectral filter was found and a different correlation between linear and circular polarization entangled state were observed. It seems that the standard theoretical models for SPDC need to be improved in order to provide a comprehensive treatment for the result of the experiment.
Polarization-entangled photon pairs can be efficiently prepared into pure Bell states with a high fidelity via type-II spontaneous parametric down-conversion (SPDC) of narrow-band pump light. However, the use of femtosecond pump pulses to generate multiphoton states with precise timing often requires spectral filtering to maintain a high quality of polarization entanglement. This typically reduces the efficiency of photon pair collection. We experimentally map the polarization correlations of photon pairs from such a source over a range of down-converted wavelengths with a high spectral resolution and find strong polarization correlations everywhere. A spectrally dependent imbalance between contributions from the two possible decay paths of SPDC is identified as the reason for a reduction in entanglement quality observed with femtosecond pump pulses. Our spectral measurements allow us to predict the polarization correlations for arbitrary filter profiles when the frequency degree of freedom of the photon pairs is ignored.