Theory of excitonic confinement in semiconductor quantum wires

We review our theoretical approach to the optical response of low-dimensional semiconductor structures. The method is based on the density-matrix formalism and can treat low-density (excitonic) and high-density (gain) regimes on the same footing while retaining the full complexity of realistic nanostructures. We discuss in particular its generalization for studying the combined effects of dielectric and quantum confinement, as well as novel developments aimed at the analysis of local absorption spectra. We examine the main effects of electron-hole Coulomb correlation on the optical spectra of semiconductor quantum wires, where it determines the suppression of band-edge singularities and the peculiar scaling properties of excitonic binding and non-linearities. On the basis of our recent results on different types of nanostructure, we present a critical discussion of possible strategies for tailoring electron-hole Coulomb interaction, and predicting its influence on near-field spectra.