Accession Number : ADA336765

Title :   Spontaneous Emission in Microcavity Lasers

Descriptive Note : Master's thesis

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH

Personal Author(s) : Ziegler, Dustin Philip

PDF Url : ADA336765

Report Date : DEC 1997

Pagination or Media Count : 119

Abstract : An understanding of spontaneous emission processes within microcavities is crucial in addressing the need to make tomorrow's microlasers more efficient. One approach to improving the device efficiency is to reduce the threshold input energy at which lasing begins to occur. It has been suggested that the threshold in a microcavity laser can be decreased by increasing the fraction of spontaneous emission into the lasing mode, this can be accomplished by preferentially coupling the gain medium of the laser to the electromagnetic cavity mode of interest. It therefore becomes necessary to understand the mechanism by which this coupling takes place. This research develops a fully quantum mechanical description of the interaction between a gain medium medeled as a two level atom and a multimode electromagnetic field in a microcavity. Atomic transition probabilities are computed for systems in which the atom couples through a single photon process to electromagnetic cavity modes which range in number from two to 2000. Calculations performed for cavities with widely spaced modes demonstrate that atoms exhibit Jaynes Cummings behavior when closely tuned to one mode. Detuning of the atom from the mode inhibits the exchange of energy, while increasing the strength of the coupling to the mode amplifies this exchange. Two level systems strongly coupled to many closely spaced modes exhibit spontaneous emission rates characteristic of an atom in free space.

Descriptors :   *LASER CAVITIES, *TUNABLE LASERS, *ELECTRON EMISSION, *DIODE LASERS, ELECTROMAGNETIC FIELDS, THRESHOLD EFFECTS, QUANTUM THEORY, THESES, FREE ELECTRON LASERS, ELECTROMAGNETIC RADIATION, GAIN, QUANTUM ELECTRODYNAMICS, DETUNING.

Subject Categories : Lasers and Masers
      Quantum Theory and Relativity

Distribution Statement : APPROVED FOR PUBLIC RELEASE