Kastler–Brossel Laboratory
The Kastler–Brossel Laboratory, (formerly the Laboratory of Hertzian Spectroscopy) located in Paris, France, is a research laboratory specializing in fundamental physics of quantum systems. Founded in 1951 by Alfred Kastler and Jean Brossel, it is a joint research unit (French UMR 8552) operated by the French National Centre for Scientific Research (CNRS), the École normale supérieure, the Sorbonne University and the Collège de France.