Alfred Kastler

Alfred Kastler (French: [kastlɛʁ]; 3 May 1902 – 7 January 1984) was a German-born French physicist and Nobel laureate in Physics. He is known for the development of optical pumping.

Kastler was born in Guebwiller (Alsace, at the time part of the German Empire), and became a French citizen when Alsace reverted to France at the end of World War I. He attended the Lycée Bartholdi in Colmar, Alsace, and then École Normale Supérieure in Paris in 1921. After his studies, he began teaching physics at the Lycée of Mulhouse in 1926, and then taught at the University 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.

Collaborating with Jean Brossel, he researched quantum mechanics, the interaction between light and atoms, and spectroscopy. Kastler, working on combination of optical resonance and magnetic resonance, developed the technique of "optical pumping". Those works led to the completion of the theory of lasers and masers.

In 1962, he received the first C.E.K Mees Medal from the Optical Society of America, and he was elected an Honorary member of the Society. The following year, he was elected a Fellow.

He won the Nobel Prize in Physics in 1966 "for the discovery and development of optical methods for studying Hertzian resonances in atoms".

He was president of the board of the Institut d'optique théorique et appliquée and served as the first chairman of the non-governmental organization (NGO) Action Against Hunger.

Kastler also wrote poetry (in German). In 1971 he published Europe, ma patrie: Deutsche Lieder eines französischen Europäers (i.e. Europe, my fatherland: German songs of a French European).

In 1976, Kastler was elected to the American Philosophical Society.