The dynamic Stark effect under a not-too-strong femtosecond excitation regime in quantum well structures

Using straightforward time-dependent perturbation treatment, transient cohe rent radiation-semiconductor interaction mechanisms are investigated analyt ically in a quantum well structure (QWS) duly irradiated by a moderate powe r femtosecond laser with photon energy slightly less than the crystal bandg ap energy. The transition energy is calculated by recognizing the finite po tential well depth of the QWS. The effects of higher excitonic states on th e Stark shift and self-energy correction are examined in GaAs/AlGaAs QWS. T he study shows a red shift with increasing excitation intensity and the shi ft is also found to be less when all the discrete excitonic states below th e band edge are considered together. An increased self-energy correction ac companies this red shift.