  Applying the Floquet theory, we developed the method to control excitonic
properties of semiconductor quantum wells by a high-frequency electromagnetic
field. It is demonstrated, particularly, that the field induces the blue shift
of exciton emission from the quantum wells and narrows width of the
corresponding spectral line. As a consequence, the field strongly modifies
optical properties of the quantum wells and, therefore, can be used to tune
characteristics of the optoelectronic devices based on them.
