Kastler was born inGuebwiller (Alsace, at the time part of theGerman Empire), and became a French citizen when Alsace reverted to France at the end of World War I. He attended theLycée Bartholdi inColmar, Alsace, and thenÉcole Normale Supérieure in Paris in 1921. After his studies, he began teachingphysics at the Lycée ofMulhouse in 1926, and then taught at theUniversity of Bordeaux, where he was a university professor until 1941.Georges Bruhat asked him to come back to the École Normale Supérieure, where he finally obtained a chair in 1952.
In 1962, he received the first C.E.K Mees Medal from theOptical Society of America, and he was elected an Honorary member of the Society. The following year, he was elected a Fellow.
He won theNobel Prize in Physics in 1966 "for the discovery and development of optical methods for studying Hertzian resonances in atoms".
Kastler also wrote poetry (inGerman). In 1971 he publishedEurope, ma patrie: Deutsche Lieder eines französischen Europäers (i.e.Europe, my fatherland: German songs of a French European).
Professor Kastler spent most of his research career at theEcole Normale Supérieure in Paris where he started after the war a small research group on spectroscopy with his student,Jean Brossel.
In December 1924, Kessler married Elise Cosset, a teacher. They had three children, Daniel, Claude-Yves, and Mireille. His sons became teachers, and Mireille became a doctor.[8]
