Abstract
With use of the photon Green’s function, the reflection and transmission coefficient associated with a lowest exciton level based on the “polariton” picture was calculated. To consider the effects of the spatial dispersion due to the translational motion of excitons, the “specular” and “diffuse” boundary conditions are adopted. The calculation based on a simple model for polaritons shows that the minimum of the transmission coefficient arises in the neighbourhood of the transverse exciton energy, and the hump may be expected at the longitudinal exciton energy.