Scientists Just Used Sunlight To Pull Off a Quantum Physics Feat Once Thought Impossible

Researchers at Xiamen University showed that tracked sunlight can pump a nonlinear crystal to generate correlated photon pairs.

Using those photons, they demonstrated high-visibility ghost imaging, a quantum optics technique once thought to require lasers.

The experiment used spontaneous parametric down-conversion in a PPKTP crystal to create the quantum light pairs.

The result points to a passive, power-free route for imaging and quantum information tasks in remote or low-power environments.