Accession Number : AD0646321

Title :   NOISE SOURCES DESCRIBING QUANTUM EFFECTS IN THE LASER OSCILLATOR.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS

Personal Author(s) : Pauwels,Herman J.

Report Date : 01 DEC 1966

Pagination or Media Count : 117

Abstract : Quantum noise in the laser means those properties of the laser output that are caused by the quantum nature of the electromagnetic field and of the material systems and reservoirs with which it interacts. It is shown that a fully quantum-mechanical treatment of the laser can be formulated in a noise-source formalism, for which the noise sources are operators. A definition is given for the Gaussian character of operators in an appropriate ensemble, and it is shown that the noise sources for the laser are Gaussian. Special laser models are treated. The first model requires that the relevant relaxation time constants of the material be much smaller than those of the field; the second model drops this restriction. The final operator equations are solved by means of a linearization approximation that is only justified for operation points 'sufficiently' above threshold. The first model takes the quantum nature of the field above threshold (or equivalently the commutator of certain noise-source operators) consistently into account; the second model neglects these quantum effects. The results are compared with the predictions of a 'semiclassical' theory in which classical equations contain noise sources that correctly represent properties of the field below threshold. (Author)

Descriptors :   (*LASERS, *FIELD THEORY), OSCILLATORS, NOISE, SOURCES, MOMENTS

Subject Categories : Lasers and Masers

Distribution Statement : APPROVED FOR PUBLIC RELEASE