LINEAR AND NONLINEAR-OPTICAL PROPERTIES OF SEMICONDUCTOR SUPERLATTICES - EXCITONIC AND FIELD-INDUCED EFFECTS

The effective dimensionality of excitons can be drastically changed by applying an alternating electric field. On the basis of a full three- dimensional description of both coherent and incoherent phenomena in a nisotropic structures it is found that appropriate applied oscillating fields change the exciton wave function from anisotropic three dimens ional to basically two dimensional. This effective-dimension change is caused by dynamic localization which leads to an increase of the exci ton binding energy and of the corresponding oscillator strength.