Claude Cohen-Tannoudji returns to the laboratory and does his Ph.D. under the supervision of A. Kastler and J. Brossel. He tries to derive a master equation for the optical pumping cycle and to understand the physics of the off-diagonal elements of the density matrix (atomic coherences). He predicts and proves a 'light shift' for the various Zeeman sublevels. Cohen-Tannoudji receives his Ph.D. in 1962.

Claude Cohen-Tannoudji is appointed Professor at the Collège de France. He enjoys the demanding yet stimulating teaching environment. In the 1980s he begins to lecture on radiative forces and sets up a research group to investigate a new cooling mechanism suggested by the dressed atom approach. They work on the correlation between spatial modulations of the dressed state energies in a high intensity laser standing wave and those of spontaneous rates between dressed states.

Claude Cohen-Tannoudji attends the Ecole Normale Supérieure in Paris to study physics and mathematics. He is facinated by lectures given by Henri Cartan, Laurent Schwartz and particularly Alfred Kastler. He joins Kastler's research group, who also trains him in pedagogics. Furthermore he attends lectures by Albert Messiah and Claude Bloch. Cohen. Tannoudji receives his diploma in 1957 and finishes his 'Agrégation' a year later.

Claude Cohen-Tannoudji, Steven Chu and William D. Philips are awarded the Nobel Prize in Physics for the development of methods to cool and trap atoms with laser light.

The research of Claude Cohen-Tannoudji's group results in the development of the 'Sisyphus cooling', a scheme in which moving atoms are running up potential hills more frequently than down. This leads to a channeling of atoms at the nodes or antinodes of a standing wave. The finding enable the group to interprete sub-Doppler temperatures observed by B. Phillips in 1988 and to apply coherent population trapping to laser cooling.

Claude Cohen-Tannoudji spends two months at the Les Houches summer school. The school offers intense training in modern physics and lectures by J. Schwinger, N. Ramsey and W. Pauli among others.

Claude Cohen-Tannoudji marries Jacqueline Veyrat in 1958. They have three children.

Claude Cohen-Tannoudji is born in Constantine, France (now Algeria) in 1933.

Claude Cohen-Tannoudji is drafted into the army and serves in the scientific department supervised by J.E. Blamont. There he studies the upper atmosphere with the help of sodium clouds.

Claude Cohen-Tannoudji attends a high school in Algiers. His family and education is largeley uneffected by the second world war and he leaves Algiers before the independence war.

Claude Cohen-Tannoudji accepts a position at the University of Paris and teaches quantum mechanics. He sets up a research group and works on atom-photon interactions in the high intensity limit where perturbative treatments are no longer valid. This leads to the development of the 'dressed atom' system. It allows the prediction of a modification of the Landé factor of an atomic level. The group proposes new physical pictures of vacuum fluctuations, radiation reaction, the Mollows triplet and photon correlations.