Spectral and intensity dependence on dipole localization in Fabry–Perot cavities

Data is presented on the characteristics of light emitted from localized dipoles contained in Fabry–Perot cavities. The cavities consist of AlGaAs semiconductor with the dipole localization achieved using GaAs quantum wells. Experimental data shows that the standard assumption of the spectral width of a cavity mode as having some fixed relationship to the photon lifetime in the cavity is an approximation which only becomes valid for dipoles throughout the cavity. Also, intensity differences are measured out either side of a cavity even when symmetrical mirrors are used. The intensity difference depends on the precise dipole position. Both the spectral and intensity differences can be derived from theory using a model which accounts for interference between coherent spontaneous wavepackets emitted in opposite directions from individual emission events.