A single camera shot stores both a normal picture and a hidden map of how light rippled through the scene. Quantum entanglement makes this possible. Pairs of linked photons are generated: one visits the object, its twin takes a detour. Later, measuring the twin one way pulls out the brightness information. Measuring it another way makes the first photon reveal its phase, the rhythm of its waves, yielding a pattern. The choice of image happens only after the light hit the sensor.

This turns the delayed-choice quantum eraser, a thought experiment by John Archibald Wheeler, into a practical tool. The team used quantum mechanics to prove it matches separate shots in accuracy with perfect alignment. The twist: the photon that struck the detector had no fixed image until its distant twin was measured, as if the past remained blurry until a future decision focused it.