Optical response in multi-quantum wells under Bragg conditions

A microscopic description of matter polarization and electromagnetic field is used to study the linear optical response of N quantum wells under Bragg condition at the resonant wavelength. In this system the radiative interaction among induced polarizations plays an essential role and the inclusion of this effect leads to a correct description of the size and internal structure dependence of the optical response.The spectral evolution of reflectivity and absorbance with increasing N from the super-radiance regime to the 1D photonic crystal limit (N ? ?) is shown.Polaritonic dispersion curves are calculated for the infinite system and compared with the photonic dispersion curves due to the background dielectric function modulation.A decomposition of the polaritonic matrix of interaction is proposed in order to separate different contributions in the optical response and to achieve a comparison with the response of a cluster of non-interacting units.