Gain and strong-signal saturation of photoexcited quantum-well structures

The stimulated emission spectra of photoexcited quantum-well structures were measured at room temperature, 77 and 1.8K as a function of the illuminated stripe length and excitation intensity. Three samples are examined: a multiple quantum well, and two superlattices (one of them is type-Il). Based on these data, the gain spectra and gain saturation behavior were obtained using Agrawal's model for the analysis. Both the spontaneous photoluminescence spectra and the stimulated emission spectra are used in order to analyze the spectral shifts. Kronig-Penney model was used to approximate the energy level diagram of our samples.