Optical properties of double cascade-type GaAs/AlGaAs multiple quantum well nanostructures via exciton spin relaxation

In this paper, we investigate the effect of incoherent pumping field and exciton spin relaxation on optical properties of four-level biexciton-exciton double cascade-type configuration. It is shown that probe absorption, dispersion and group velocity can be controlled via incoherent pumping field and exciton spin relaxation. Also it is found that the probe absorption is converted to the probe gain in the presence of population inversion.