The sagnac effect in optically active media

The propagation of a plane, homogeneous and transverse electromagnetic wave through an optically active medium, at rest in an inertial frame or on a uniformly rotating disc, is studied here. This problem is associated with the well known Sagnac effect. The shift of fringe order one in an interferometer due to the rotation is calculated. The solution of the resulting eigenvalue problem is based on a perturbation technique in which only terms up to the first order in the rotation and the optical activity coefficient are retained.