Generating quantum-entangled photon pairs directly using natural sunlight rather than artificial lasers

https://www.eurekalert.org/news-releases/1139133

"focusing solar concentrator collected sunlight into thin fiber, then routed into nonlinear crystal, achieves spontaneous 94% entanglement fidelity parametric down-conversion, matching laser bandwidth normalized performance... sunlight effective, efficient pump source so can rely only on polarization alignment rather than spatial/ temporal coherence... no bulky onboard lasers/ complex power conversion... quantum key distribution, space-based quantum networks, off-grid/ satellite and space quantum sensing"