Pump–probe experiments are used as a controllable way to investigate the properties of photoexcited semiconductors, in particular, the absorption saturation. We present an experiment–theory comparison for ZnSe quantum wells, investigating the energy renormalization and bleaching of the excitonic resonances. Experiments were performed with spin-selective excitation and above-bandgap pumping. The model, based on the semiconductor Bloch equations in the screened Hartree–Fock approximation, takes various scattering processes into account phenomenologically. Comparing numerical results with available experimental data, we explain the experimental results and find that the electron spin-flip occurs on a time scale of 30 ps.
© 2002 Optical Society of America
(190.0190) Nonlinear optics : Nonlinear optics
(190.5970) Nonlinear optics : Semiconductor nonlinear optics including MQW
(190.7110) Nonlinear optics : Ultrafast nonlinear optics
(320.0320) Ultrafast optics : Ultrafast optics
(320.7130) Ultrafast optics : Ultrafast processes in condensed matter, including semiconductors
H. Ouerdane, G. Papageorgiou, I. Galbraith, A. K. Kar, and B. S. Wherrett, "Ultrafast pump–probe dynamics in ZnSe-based semiconductor quantum wells," J. Opt. Soc. Am. B 19, 2022-2031 (2002)