Major developments in atomic physics and optics over the last fifty years

The first lesson was an introduction to this review of revolutions in atomic physics and quantum optics. It began with a brief description of the major milestones in atomic physics, first recalling the state of the art in the immediate post-war years: atomic and molecular jet spectroscopy, nuclear magnetic resonance, the first test experiments in quantum electrodynamics, including the measurement of the electron's anomalous magnetic moment and the Lamb shift. The review went on to emphasize the importance of double resonance and optical pumping methods, developed by Jean Brossel and Alfred Kastler in the 1950s, which were the first examples of the manipulation of atoms by light, even before the advent of the laser. The beginnings of this new light source were then described, as were its first applications in physics from the 1960s, leading to the birth of non-linear optics and the so-called saturated absorption method. The 1970s saw the development of frequency-tunable lasers, which led to an explosion in high-resolution spectroscopy methods, freeing us in various ways from the broadening of atomic and molecular lines due to the Doppler effect. The lesson then briefly outlined the major advances of the 1980s, including the development of laser-induced atom cooling and trapping methods. In the same decade, parallel advances in trapped-ion experiments and cavity quantum electrodynamics with Rydberg atoms enabled the first observations of isolated quantum systems. The 1990s saw the first applications of the manipulation of these systems to quantum information, with simple demonstrations of quantum gates and entanglement, as well as the study of decoherence. In the same decade, the physics of cold atoms led to the realization of Bose Einstein condensates, paving the way for an extremely fertile field of research that was to explode in the 2000s. This decade and the years that followed saw a major expansion in research into quantum gases (degenerate bosons and fermions), as well as quantum information with real and artificial atoms (quantum circuits including Josephson junctions). It has also seen considerable progress in the precision of spectroscopic measurements and atomic clocks (development of optical frequency combs) and in the study of ultrafast phenomena in atomic, molecular and Quantum Condensed Matter Physics (exploitation of "attosecond" light pulses).