This book is an edited version of lectures given by the authors at the 1985 Summer School on Lase Physics. The School was held in Jilin University in Changchun, Peoples' Republic of China. Contents: The book is divided into 2 parts, the first is ''An Outline of Laser Physics and Laser Instabilities'': An Introduction to the Theory of the Laser: The Rate Equations; The Interaction of Light and Matter: The Classical Picture; The Basic Laser Equations: Homogeneously Broadened Systems; Steady State Behavior of a Homogeneously Broadened Ring Laser; Linear Stability Analysis: The Resonant Case; The Adiabatic Elimination of the Fast Variables; Linear Stability Analysis: The General Case; The Single Mode Laser: Deterministic Chaos; Dynamical Behavior of the Maxwell-Bloch Equations; The Spectral Analysis of the Output Field; Theory of a Laser with Inhomogeneous Broadening. The second part is on the ''principles of Laser Physics and Laser Instabilities'': Background Notes for the Discussion of Experimental Laser Systems; Amplified Spontaneous Emission; The Two-Level Atom; Laser Cavities and Modes; Types of Laser Systems and Classification of Lasers; the Xe 3.51 ..mu..m Laser; Chaos in Single Mode Lasers; Forced Laser Systems, Modulated Lasers and Lasers with an Injected Signal; Dynamical Phenomena in Multimode Laser Systems.
An atom laser is a hypothetical device which would produce an atomic field analogous to the electromagnetic field of a photon laser. Here I argue that for this analogy to be meaningful it is necessary to have a precise definition of a laser which applies equally to photon or atom lasers. The definition I propose is based upon the principle that the output of a laser is well-approximated by a classical wave of fixed intensity and phase. This principle yields four quantitative conditions which the output of a device must satisfy in order for that device to be considered a laser. While explaining these requirements, I analyse the similarities and differences between atom and photon lasers. I show how these conditions are satisfied first by an idealized photon laser model, and then by a more generic model which can apply to atom lasers also. Lastly, I briefly discuss the current proposals for atom lasers and whether they could be true lasers.