Basic Theory of Lasers and Masers: A Density Matrix Approach

Jacques Vanier

Christopher Feuillade, John G. Baker, C. Böttcher

Boris Volodumurovich Bondarev

Donald W. Goodwin

Jacques Vanier London: Gordon and Breach 1971 pp 115 price £4.75 This monograph, one in the Documents in Modern Physics series, describes the density matrix formalism as applied to problems in basic quantum electronics. The first chapter gives a brief introduction to those aspects of quantum mechanics essential to an understanding of the following chapters.

Peter X. Hammerling

The theory of an optical maser in the presence of an external static magnetic field has been discussed recently by several authors. It is shown here that a considerable simplification of the theory results when one uses a tensor operator expansion of the density matrix describing the system.

Marlan O. Scully, Willis E. Lamb

A quantum statistical analysis of an optical maser is presented in generalization of the recent semiclassical theory of Lamb. Equations of motion for the density matrix of the quantized electromagnetic field are derived. These equations describe the irreversible dynamics of the laser radiation in all regions of operation (above, below, and at threshold). Nonlinearities play an essential role in this problem. The diagonal equations of motion for the radiation are found to have an apparent physical interpretation. At steady state, these equations may be solved via detailed-balance considerations to yield the photon statistical distribution ${\ensuremath{\rho}}_{n,n}$. The resulting distribution has a variance which is significantly larger than that for coherent light. The off-diagonal elements of the radiation density matrix describe the effects of phase diffusion in general and provide the spectral profile ${| E(\ensuremath{\omega}) |}^{2}$ as a special case. A detailed discussion of the physics involved in this paper is given in the concluding sections. The theory of the laser adds another example to the short list of solved problems in irreversible quantum statistical mechanics.