Story perspectives

Sunlight Powers Entangled Photons, Beats Bell’s Inequality

8/6/2026

Summary

Story summary

Researchers at the University of Ottawa and the Max Planck Institute generated entangled photon pairs using focused sunlight.
Cheng Li designed a solar-tracking system with a window-sized Fresnel lens and a cone concentrator.
After three days of testing, the system produced photon pairs with ~94 % fidelity and violated Bell’s inequality.
Li said optical distortions cause shortfall from laser sources and that the team aims to boost brightness for field-deployable, sunlight-powered quantum-encryption devices.

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Story summary

Researchers at the University of Ottawa and the Max Planck Institute generated entangled photon pairs using focused sunlight.
Cheng Li designed a solar-tracking system with a window-sized Fresnel lens and a cone concentrator.
After three days of testing, the system produced photon pairs with ~94 % fidelity and violated Bell’s inequality.
Li said optical distortions cause shortfall from laser sources and that the team aims to boost brightness for field-deployable, sunlight-powered quantum-encryption devices.