Many Atoms in a Cavity: Macroscopic Theory

Abstract

We will be familiar with much of the background to many-atom cavity QED from our treatment of laser theory in Chaps. 7 and 8. Laser theory is closely related to the theory of optical bistability, which is also built around the quasiresonant interaction of atoms and light inside an optical cavity, but considers a passive rather than active medium. In this chapter we develop the semiclassical theory of optical bistability and uncover its most obvious connections with cavity QED—in particular, the many-atom version of the vacuum Rabi doublet. We meet the Maxwell–Bloch equations for a two-level medium interacting with a single mode of a Fabry–Perot, and discuss the relationship between these macroscopic equations and a microscopic description in terms of Hamiltonians and master equations.