This thesis describes a theoretical and experimental investigation of the intensities, linewidths, and frequencies of radiation by an atom in an optical resonator. It is found that the atom's spontaneous emission rate may be enhanced or inhibited, depending on the tuning of the resonator, and its transition frequencies shifted. A simple classical description of these effects is given in which t...

We propose a method to overcome Auger recombination in nanocrystal quantum dot lasers using cavity-enhanced spontaneous emission. We derive a numerical model for a laser composed of nanocrystal quantum dots coupled to optical nanocavities with small mode-volume. Using this model, we demonstrate that spontaneous emission enhancement of the biexciton transition lowers the lasing threshold by redu...

Low-threshold lasing is observed at the edge of the stop band of a one-dimensional structure-a dye-doped cholesteric liquid-crystal film. The mode closest to the edge has the lowest lasing threshold. The rates of spontaneous and stimulated emission are suppressed within the stop band and enhanced at the band edge. The ratio of right to left circularly polarized spontaneous emission is in good a...

We have demonstrated that by adding the solution of aggregated silver nanoparticles to the solution of rhodamine 6G dye, one can enhance the efficiency of spontaneous and stimulated emission. We attribute an increase of the spontaneous emission intensity of dye to the increase of the absorption efficiency caused by the field enhancements in metallic nanostructures associated with surface plasmo...

Spontaneous emission from quantum-well excitons in a thin, high-refractive-index dielectric layer embedded in a low-refractive-index bulk dielectric is studied as a function of the layer thickness and refractive-index ratio. Total spontaneous emission rates for a thin layer decrease linearly with the index ratio for dipoles in the plane of the layer and as the fifth power of the index ratio for...

The noise characteristics of vertical-cavity surface-emitting (VCSE) lasers are studied by using the Langevin rate equations modified suitably to include the enhanced spontaneous emission occurring in such microcavity lasers. The intensity and frequency noise spectra show the effects induced by suppression of relaxation oscillations. However, such a suppression depends on the output power as we...

Engineering the surrounding electromagnetic environment of light emitters by photonic engineering, e.g. photonic crystal cavity, can dramatically enhance its spontaneous emission rate through the Purcell effect. Here we report an enhanced spontaneous emission rate of monolayer molybdenum disulfide (MoS2) by coupling it to a 1D silicon nitride photonic crystal. A four times stronger photolumines...

The influence of spontaneous emission on the dynamical localization in atomic momentum transfer observed in recent experiments is investigated. Our numerical and analytical results indicate that contrary to previous expectation quantum diffusion due to decoherence by spontaneous emission is non-negligible in the experimental regime and may actually be visible in the measured data. Modifications...

We propose two quantum error correction schemes which increase the maximum storage time for qubits in a system of cold trapped ions, using a minimal number of ancillary qubits. Both schemes consider only the errors introduced by the decoherence due to spontaneous emission from the upper levels of the ions. A watchdog approach is adopted in conjunction with selective coherent feedback to elimina...

We show that the two-photon transition rates of quantum dots coupled to nanocavities are enhanced by up to several orders of magnitude relative to quantum dots in bulk host. We then propose how to take advantage of this enhancement to implement coherent quantum-dot excitation by two-photon absorption, entangled photon pair generation by two-photon spontaneous emission, and single-photon generat...