Saturation and self-lensing in self-assembled quantum dots with constant-wave driving

The nonlinear optical response of self-assembled quantum dots to cw driving is analyzed via numerical simulations of a spatially resolved rate equation model. The saturation is shown to follow a behavior in between the one for a dominantly, homogeneously, and inhomogeneously broadened medium. Self-lensing is suggested to probe the refractive-index nonlinearities and to open a complementary way of characterizing phase-amplitude coupling (alpha factor) in quantum-dots samples. For conservative assumptions on current samples the minimum focal length is predicted to be +/-1.7 mm for an input beam with 15 mu m radius at a detuning of 1.1 inhomogeneous linewidths from gain center.