The proposed research is an investigation into the nonlinear optical properties of selected semiconductor superlattices. The work will specifically focus on optically induced changes near the excitonic resonances in II-VI compound semiconductors such as (Zn, Mn)Se and (Cd, Mn)Te. These materials are unique in that strongly coupled electronic and magnetic excitations are optically accessible. The proposed studies combine two aspects of new and advanced research, first, the use of sophisticated transient optical techniques on picosecond and femtosecond timescale, and second, the spectroscopy of novel ultrathin semiconductor layered superlattice structures. The basic portion of the work involves the characterization of the largely unknown exciton kinetics on such timescale while the more applied part focuses on the enhancement of the sought transient nonlinearities in a high density magnetically oriented exciton system. The longer term impact of this research includes possibilities for ultrafast optical switches and logic elements.
