Dressed-band approach to laser-field effects in semiconductors and quantum-confined heterostructures

Abstract

A theoretical study of the effects of a laser field on the electronic and optical properties of GaAs-(Ga,Al)As heterostructures is presented by using a Kane model for the GaAs bulk semiconductor and working within an extended dressed-atom approach. For a laser tuned far below any resonances, the effects of the laser-semiconductor interaction correspond to a renormalization of the semiconductor energy gap and conduction/valence effective masses. This renormalized one-body approach may be used to give a qualitative indication of the laser effects on a variety of optoelectronic phenomena in semiconductor heterostructures for which the effective-mass approximation provides a good physical description. As a test, the exciton Stark shift in quantum wells is calculated and the effects due to the band-structure laser dressing are found to be of the same order of magnitude as those obtained from many-body diagrammatic techniques. We have also analyzed the effects of laser dressing on the shallow-donor peak energies in quantum wells, and found them comparable with; those produced by a magnetic field of a few teslas.