Sciences, Philosophie, Histoire – UMR 7219, laboratoire SPHERE

Quantum optics is the branch of physics that describes light and its interactions with matter using quantum theory. Its genesis, at the beginning of the 1960s, marks a crucial and yet unknown period in the history of light. Until then, light was considered sometimes in an undulatory way, sometimes in a corpuscular way. In the 19th century, Thomas Young, Augustin Fresnel and later James Clerk Maxwell established the wave theory of light. At the beginning of the 20th century, Albert Einstein proposed a corpuscular conception of light, introducing in physics the idea of "quantum of light" later called "photon".
However, this idea did not prevail in the field of traditional optics, so that the physicists who were working in this field in the 1950s were sticking to a wave vision of light, very effective in describing optical phenomena. This was the case with Max Born and Emil Wolf, who published a reference book in 1959 in classical optics entitled Principles of Optics.
It was then that two important events occurred: the experiments conducted in England by physicists Robert Hanbury Brown and Richard Twiss, as well as the invention of the laser. By trying to explain these two phenomena with quantum methods, the American physicist Roy Glauber established a new theory in 1963 quantum of light (more precisely of the concept of coherence). This theory offered a whole new perspective on light. However, not everyone agreed with this conceptual revolution, which led to debates for many years.
It is this episode in the history of physics that changed optical practices and which, however, remains largely unexplored. For example, the works of French physicists who have distinguished themselves in quantum optics in the years 1960 - 1980 in Paris and Orsay have never really been the subject of a historical analysis. Two historians have really looked at this period: Joan Lisa Bromberg, who focused her research on lasers in America (1950 - 1970), and Olival Freire, who focused on the controversies surrounding the concept of photon and quantum optics experiments concerning Bell’s inequalities. years.
It is this episode in the history of physics, which changed the practices of optics and which remains however very little explored, that I propose to study. For example, the work of French physicists who distinguished themselves in quantum optics in the 1960s and 1980s in Paris and Orsay has never really been the subject of systematic historical analysis. Two historians have certainly studied this period: Joan Lisa Bromberg, who focused her research on lasers in America, and Olival Freire, who was interested in the controversies surrounding the concept of photon and quantum optics experiments concerning Bell’s inequalities. But in this work, quantum optics remains a secondary subject.

The aim of this PhD is therefore to trace the development of quantum optics over the years 1960 to the 1980s by placing it in an experimental, institutional, economic and political context, thus giving the subject an overall coherence.