Modification of Spontaneous Emission and Applications to Semiconductor Lasers.
UNIVERSITY COLL LONDON (UNITED KINGDOM)
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In an earlier report, we have shown for the first time how that zero lasing threshold is achieved between a pair of mirrors spaced at a distance of a half a wavelength of the lasing radiation mod, while spontaneous emission is only partially suppressed. However, the residual spontaneous emission must be taken into account when considering laser characteristics other than the threshold pumping rate, for example, laser linewidth. The present report is concerned with a quantum mechanical model of the laser under conditions of suppressed spontaneous emission. For almost fully inhibited spontaneous emission, the accepted laser models are not applicable, since they are based on a statistical approach valid when a large number of modes participate in the spontaneous emission loss. For a partial suppression of spontaneous emission, the model is applicable, mainly with modification of the atomic decay rate. It is found that when zero threshold is obtained between mirrors as mentioned above, the laser linewidth is reduced only by a modest factor of a quarter.
- Lasers and Masers
- Quantum Theory and Relativity