Publications

Many-body effects in quantum-dot lasers

Schneider, Hans C.; Chow, Weng W.; Smowton, Peter M.; Pèarce, Emma J.; Koch, Stephan W.

We investigate the influence of the coupling between localized and continuum states on the optical gain and refractive index in self-organized quantum-dot structures under high-excitation conditions. For wide-bandgap nitride-based quantum-dot structures we show that the presence of strong many-body Coulomb interactions and the quantum-confined Stark effect result in absorption/gain features that depend on the quantum-dot dimensions in a nontrivial way. For InAs/GaAs based quantum dots, we investigate the refractive index properties and show that negative α. or linewidth enhancement factors may occur in these systems, which makes the beam quality (filamentation) properties of quantum-dot lasers very different from quantum-well lasers. This is consistent with measurements which show a reduction in quantum-dot laser filamentation as the injection level is increased.