Fifty years ago, R. Hanbury Brown and R.Q. Twiss invented a new method for measuring the diameter of stars, based on the effect of "photon bunching". Their publication prompted a hot controversy about the understanding of their effect: how could photons emitted by opposite edges of a star exhibit bunching, ie lack of statistical independence? The confusion increased yet more when it was realised that laser light does NOT exhibit bunching, and it is partly for clarifying these points that R Glauber developped the formalism of modern quantum optics. This effect has more recently been observed with atoms, and we will present these recent experiments in the light of the discussions about photons, focusing on our recent experiments at Institut d'Optique.
Born in 1947, Alain Aspect studied at the Ecole Normale Supérieure de Cachan and Université d’Orsay. After a master thesis on holography and a three years teaching assignment in Cameroon, he started, in 1974, a series of experiments on the foundations of quantum mechanics. His “Experimental Tests of Bell’s Inequalities with Correlated Photons”, were the subject of his doctorate thesis presented in 1983. In 1983-86, with his student Philippe Grangier, he developed the first source of single photons and performed fundamental experiments on wave-particle duality of light.
From 1985 to 1992 he worked with Claude Cohen-Tannoudji at the Laboratoire Kastler Brossel de l’ENS and Collège de France, on cooling atoms with lasers, in particular “cooling below the one photon recoil”.
Since 1991, he is head of the Atom Optics group that he has established at the Institut d’Optique, now in Palaiseau. Recent scientific production concerns mainly Bose Einstein Condensates, Atom Lasers, Quantum Atom Optics with metastable Helium, Anderson localization of ultracold atoms.
A CNRS senior scientist (”Directeur de recherches CNRS”) at Laboratoire Charles Fabry de l’Institut d’Optique, Alain Aspect is also a professor at Institut d’Optique and Ecole Polytechnique, Palaiseau.
He is a member of the French Académie des Sciences, and of the Académie des Technologies, as well as of foreign academies (NAS, USA; OAW, Austria). He has received major awards, among them the OSA Max Born award (1999), the CNRS Gold Medal (2005), the Quantum Optics senior prize of the European Physical Society (2009), the Wolf prize in Physics (2010).