PHY208 - Atoms and Lasers (2019-2020)

Light amplification by stimulated emission of radiation (laser) holds a unique place in the heart of physicists. Lasers are at the same time a spectacular manifestation of a quantum phenomenon, a powerful and versatile tool ranging from industrial applications (laser processing, telemetry...) to fundamental research (spectroscopy, cold atoms,...) and a remarkable workbench to acquire a better understanding of key concepts in physics.

PHY208 is an introduction to light-matter interactions through the intricate relationship between atoms and lasers. Importantly, this course will build on experimental situations, and introduce models with increasing complexity to explain the observed results. As the basic component of a laser is a source of light, the course will start with basic spectroscopy, and several atomic models will be considered (Bohr model, Einstein coefficients, Schrodinger model, etc.). The emission of continuous laser light by such atoms will be described from both a classical (effective medium) and semi-classical (population inversion) perspective. The mirror will then be turned back on the atoms, and several applications of laser light revealing the behavior of atoms will be discussed (Light, Stark and Zeeman shift, Rabi oscillations etc.). Finally, some practical perspectives on advanced laser technologies and applications will be given.

This course will not add many new physical concepts, but rather show how results obtained in previous courses (especially in optics, classical and quantum mechanics) can be used. Upon completion of this course, students will have acquired key understandings concerning the bilateral interactions between laser devices and atoms. They will have understood the circumstances under which the emission of useful coherent light can be produced, and also the information that such light can provide when analyzing atomic systems. They will also be able to identify the relevance, necessity, and limitations that classical and quantum models display when analyzing problems in this field. They will also gain familiarity with some laser device technologies.