Philippe Grangier

Biography

He studied at the École Normale Supérieure and the University of Paris-Sud. He worked at the Institut d'Optique in Palaiseau, where he leads the quantum optics group. Winner of the Balzan Prize, the Albert Einstein Medal. Member of the French Academy of Sciences.

Key discoveries

• Photon antibunching: first observed that a single atom emits photons one at a time, not in bunches, which became direct proof of the quantum nature of light (1986).
• Plug-and-play quantum cryptography: developed a practical scheme for quantum key distribution with automatic compensation of polarization distortions, widely used in commercial systems.
• Bell inequalities: conducted precision experiments closing loopholes in tests of local realism.