He shared the 1997 Nobel Prize in Physics with Steven Chu and William Daniel Phillips for research in methods of laser cooling and trapping atoms.

In 1960 he resumed working toward his doctorate, which he obtained from the École Normale Supérieure under the supervision of Alfred Kastler and Jean Brossel at the end of 1962.

[2] His lecture notes were the basis of the popular textbook, Quantum Mechanics (French: Mécanique quantique), which he wrote with his colleagues Bernard Diu [fr] and Franck Laloë.

[12] His work eventually led to the Nobel Prize in physics in 1997 "for the development of methods to cool and trap atoms with laser light", shared with Steven Chu and William Daniel Phillips.

The declaration was signed by a total of 76 Nobel Laureates and handed to then-President of the French Republic, François Hollande, as part of the successful COP21 climate summit in Paris.