Related Experiment Video
Updated: Jun 22, 2026

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
The quest for three-color entanglement: experimental investigation of new multipartite quantum correlations
K N Cassemiro1, A S Villar, M Martinelli
1Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, São Paulo, SP, Brazil 05315-970.
Abstract:
We experimentally investigate quadrature correlations between pump, signal, and idler fields in an above-threshold optical parametric oscillator. We observe new quantum correlations among the pump and signal or idler beams, as well as among the pump and a combined quadrature of signal and idler beams. A further investigation of unforeseen classical noise observed in this system is presented, which hinders the observation of the recently predicted tripartite entanglement. In spite of this noise, current results approach the limit required to demonstrate three-color entanglement.
Related Concept Videos
2D NMR: Overview of Heteronuclear Correlation Techniques
Extended Versions of Green’s Theorem
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
Green’s Theorem
The Pauli Exclusion Principle
Interpreting ¹H NMR Signal Splitting: The (n + 1) Rule
