Berreman-matrix formulation of light propagation in stratified anisotropicchiral media

We critically analyze the problem of light propagation in stratified birefr ingent gyrotropic media by introducing a 4 x 4 matrix formulation. As a tes t model we consider the case of short-pitch chiral smectic-C liquid crystal s, for which simple descriptions in terms of an effective gyrotropic homoge neous model and of a microscopic periodic structure are available. By compa ring reflectances and transmittances from finite and semi-infinite slabs, w e show that the homogeneous description is unable to account for some of th e properties of the underlying periodic structure, whatever small is the pi tch with respect to the light wavelength.