Absorption, transmission, and reflection spectra of mono- And bimolecular layers

A microscopic theory of the optical properties of mono- and bimolecular layers is described. Intermolecular interactions are assumed to be of the point dipole type. It is shown how the refractive index of a mono- or bilayer may be defined and connections to the refractive index of a three dimensional crystal are established. At frequencies close to an absorption band, strong exciton-photon coupling is shown to result in excited states with very short radiative lifetimes.