Optical gain and lasing in self-assembled InP/GaInP quantum dots

Abstract

Optical gain measurements have been performed on self-assembled InP quantum dots embedded in GaInP. The dots are formed during the growth of InP on GaInP by molecular beam epitaxy due to the strong lattice mismatch and are overgrown with GaInP afterwards. The optical gain spectra show two peaks which could be clearly identified by their polarization properties as being due to the quantum dots and the wetting layer, respectively. As expected from the results of the gain measurements, optical pumping of cleaved samples at room temperature leads to lasing of either the quantum dots or the wetting layer, depending on the experimental conditions.