Quantum Langevin theory of excess noise in lasers - art. no. 023806

In an earlier work [P. J. Bardroff and S. Stenholm, Phys. Rev. A 60, 2529 ( 1999)], we have derived a fully quantum-mechanical description of excess no ise in strongly damped lasers. This theory is used here to derive the corre sponding quantum Langevin equations. Tailing the semiclassical limit of the se we are able to regain the starting point of Siegman's treatment of exces s noise [Phys. Rev. A 39, 1253 (1989)]. Our results essentially constitute a quantum derivation of his theory and allow some generalizations.