EVALUATION OF THE HARTREE-FOCK THEORY OF THE EXCITONIC OPTICAL STARK-EFFECT

Semiconductor band-edge absorption spectra of a probe beam under the action of a nonresonant pump beam are evaluated and analyzed, both for two and three dimensional systems. Many-body effects such as phase space filling and carrier-carrier Coulomb interactions are included within the Hartree-Fock approximation. In contrast to the atomic optical Stark effect one obtains an exciton blue shift with a nearly constant (2d) or slightly increasing (3d) exciton oscillator strength. In addition, effects due to the time dependence of the fields are studied. Deviations from the time independent Hartree-Fock calculations occur both with respect to the shift itself and with respect to the shape of the outcoming signal. The results do not reflect all features of earlier experiments, but they are in agreement with recent experimental observations.