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

Research in Optical Sciences

Spectral homodyne detection, resonator detection, and entanglement in the above-threshold OPO

F. A. S. Barbosa, A. S. Coelho, K. N. Cassemiro, Claude Fabre, P. Nussenzveig, Alessandro S. Villar, M. Martinelli

Published Jan 1, 2014• 0 citations
Publisher

Abstract

In the spectral domain, the quantum state of the three beams emitted by an above-threshold optical parametric oscillator encompasses six modes. We use resonator detection to characterize hexapartite entanglement.
DOI
10.1364/qim.2014.qw4a.1

Related papers

Continuous-Variable Measurements of Non-Classical Light

F. A. S. Barbosa, A. S. Coelho, K. N. Cassemiro +4 more

In recent years we have investigated pump-signal-idler entanglement in the above-threshold optical parametric oscillator. Spectral homodyne-type detection probes two sidebands at a given analysis frequency per beam. Hexapartite entanglement is observed.

Frontiers in Optics•Jan 1, 2012•0 citations

Quantum state reconstruction of spectral field modes: Homodyne and resonator detection schemes

F. A. S. Barbosa, A. S. Coelho, K. N. Cassemiro +4 more

We revisit the problem of quantum state reconstruction of light beams from the photocurrent quantum noise. As is well known, but often overlooked, two longitudinal field modes contribute to each spectral component of the photocurrent (sideband modes). We show that spectral homodyne detection is intrinsically incapable of providing all the information needed for the full reconstruction of the two-mode spectral quantum state. Such a limitation is overcome by the technique of resonator detection. A detailed theoretical description and comparison of both methods is presented, as well as an experiment to measure the six-mode quantum state of pump-signal-idler beams of an optical parametric oscillator above the oscillation threshold.

arXiv:1310.2427•Physical Review A•Nov 14, 2013•45 citations

Full characterization of bipartite entangled states by means of a single homodyne detector

Virginia D’Auria, Salvatore Antonio Fornaro, A. Porzio +2 more

The authors address the complete experimental characterization of bipartite Gaussian entangled states. Continuous-wave (CW) entangled light beams are generated by a frequency degenerate type-II optical parametric oscillator (OPO) below threshold and their covariance matrix (CM) is fully reconstructed by using a novel scheme that involves a single homodyne detector.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2009•30 citations

Hexapartite entanglement in a CW Optical Parametric Oscillator

F. A. S. Barbosa, A. S. Coelho, Lorenzo Fonseca Martínez +4 more

The optical parametric oscillator (OPO) is a non-linear optical device capable of producing an effective interaction among optical modes with different colors. Up to now, it was believed that only three modes would be involved in the interaction. By developing a new theoretical model to analyze the sideband structure of entanglement, we show that in fact six modes are involved in the stimulated parametric interaction. We experimentally investigate how those modes are entangled to one another, in particular showing that the hexapartite entanglement can be thought of as being generated by a combination of two-mode squeezers and beam splitter Hamiltonians acting on six different colors of light.

•Dec 5, 2017•0 citations

Hexapartite Entanglement in an above-Threshold Optical Parametric Oscillator

F. A. S. Barbosa, A. S. Coelho, Luis F. Muñoz-Martínez +4 more

We demonstrate, theoretically and experimentally, the generation of hexapartite modal entanglement by the optical parametric oscillator (OPO) operating above the oscillation threshold. We show that the OPO generates a rich structure of entanglement among sets of six optical sideband modes interacting through the nonlinear crystal. The class of quantum states thus produced can be controlled by a single parameter, the power of the external laser that pumps the system. Our platform allows for the generation of massive entanglement among many optical modes with well defined but vastly different frequencies, potentially bridging nodes of a multicolor quantum network.

arXiv:1712.01756•Physical Review Letters•Aug 13, 2018•50 citations

Bright Entangled Beams from an Above-Threshold Optical Parametric Oscillator

K. N. Cassemiro, Alessandro S. Villar, Paulo Valente +2 more

We generated bright entangled beams in an optical parametric oscillator, operating above threshold. Tripartite pump-signal-idler entanglement, all with different frequencies, was also predicted and three-color quantum correlations already measured.

The Rochester Conferences on Coherence and Quantum Optics and the Quantum Information and Measurement meeting•Jan 1, 2007•1 citation
We revisit the problem of quantum state reconstruction of light beams from the photocurrent quantum noise. As is well known, but often overlooked, two longitudinal field modes contribute to each spectral component of the photocurrent (sideband modes). We show that spectral homodyne detection is intrinsically incapable of providing all the information needed for the full reconstruction of the two-mode spectral quantum state. Such a limitation is overcome by the technique of resonator detection. A detailed theoretical description and comparison of both methods is presented, as well as an experiment to measure the six-mode quantum state of pump-signal-idler beams of an optical parametric oscillator above the oscillation threshold.
The optical parametric oscillator (OPO) is a non-linear optical device capable of producing an effective interaction among optical modes with different colors. Up to now, it was believed that only three modes would be involved in the interaction. By developing a new theoretical model to analyze the sideband structure of entanglement, we show that in fact six modes are involved in the stimulated parametric interaction. We experimentally investigate how those modes are entangled to one another, in particular showing that the hexapartite entanglement can be thought of as being generated by a combination of two-mode squeezers and beam splitter Hamiltonians acting on six different colors of light.
We demonstrate, theoretically and experimentally, the generation of hexapartite modal entanglement by the optical parametric oscillator (OPO) operating above the oscillation threshold. We show that the OPO generates a rich structure of entanglement among sets of six optical sideband modes interacting through the nonlinear crystal. The class of quantum states thus produced can be controlled by a single parameter, the power of the external laser that pumps the system. Our platform allows for the generation of massive entanglement among many optical modes with well defined but vastly different frequencies, potentially bridging nodes of a multicolor quantum network.