Laser physics

Over a few years, the laser (Light Amplification by Stimulated Emission of Radiation) went from the category of laboratory equipment for the physicist to very widespread industrial usage.

The purpose of this article is to provide the many non-specialist users with an understanding of the operation of this very special light source and familiarization with its different practical configurations.

The presentation consists firstly in a discussion of the various physical phenomena contributing to the emission of coherent light and of the particular properties of this light. The following article discusses the principal devices available on the market, while respecting the traditional classification into two families: solid-state lasers and gas lasers. Before reading this text, it may be beneficial to consult a few articles on the subject “ optics ” in the sections on Basic Sciences, especially “ wave optics ”, “ optics of material media ” and “ optical coherence ”.

The profuse applications of lasers are not considered in this article. The reader interested in a specific application area can find the relevant information in the specialized treatments: mechanics (mechanics of materials, manufacturing), electricity (electro-optics, communications)...