Nanostructures in a dielectric matrix

We review the electronic and optical properties of nanostructures embedded in a dielectric matrix. In the introduction the effect of confinement on the excitonic parameters, binding energy, electron-hole interaction, oscillator strength is considered. The first part of the communication is devoted to the modification of Coulomb interaction by the dielectric constant of the environment in thin films and nanocrystals. In the second part we describe the modification of the coupling with light when the size of the object is less than the wavelength of light. (orig.)