The influence of dynamical correlations in semiconductor plasmas on optical spectra

On the basis of a nonequilibrium Green's function technique we determine a Bethe-Salpeter equation describing the linear response of a semiconductor under plasma excitation. Dynamical correlations entering the effective screened e-h interaction are treated on the basis of the full RPA polarization function. Numerical results for optical gain and absorption spectra are presented for various temperatures and densities. The validity of the commonly used plasmon pole approximation with regard to the lineshape of optical spectra is critically investigated.