Classical derivation of the laser rate equation
Abstract
In this paper, the rate equation for the energy (photon) density inside the resonant cavity of a laser oscillator is derived from Maxwell's equations. By comparison to the familiar photon rate equation, this classical derivation can be used to obtain the wellknown expression for the ratio of the power that is spontaneously emitted into a single laser mode relative to the total amount of spontaneous emission. This independent derivation does not require mode counting procedures and settles the following question: what fraction of the total power that is spontaneously emitted into the wavelength range of the fluorescent linewidth is utilized for increasing the energy in a given laser mode?
 Publication:

IEEE Journal of Quantum Electronics
 Pub Date:
 August 1983
 DOI:
 10.1109/JQE.1983.1072025
 Bibcode:
 1983IJQE...19.1228M
 Keywords:

 Decay Rates;
 Field Mode Theory;
 Laser Cavities;
 Maxwell Equation;
 Radiant Flux Density;
 Spontaneous Emission;
 Cavity Resonators;
 Fluorescence;
 Laser Modes;
 Optical Resonators;
 Spectral Line Width;
 Lasers and Masers