OPTICAL NONLINEARITIES IN UNDOPED AND MODULATION-DOPED Zn1-xCdxSe/ZnSe QUANTUM WELL STRUCTURES FABRICATED BY MOLECULAR BEAM EPITAXY

We study optical non-linearities in undoped and modulation doped Zn1-xCdxSe/ZnSe quantum well structures. In the undoped structures the exciton bleaching was investigated by the pump and probe technique, while in modulation doped structures the reduction of the exciton oscillator strength was studied as a function of doping concentration. The critical density for exciton bleaching is estimated, and the experimental data are analized by a theoretical model including many-body effects.