We consider the propagation of electromagnetic waves in a two-dimensio
nal polarizable medium endowed with Chern-Simons terms. The dispersion
relation (refractive index) of the waves is computed and the existenc
e of linear birefringence and anomalous dispersion is shown. When abso
rption is taken into account we find the classic signature of a Voigt
effect. In the case where linearly polarized, three-dimensional waves
pass through a two-dimensional plane we show that there is optical act
ivity and compute the analog of Verdet's constant.