circularly birefringent e x p l a i n

The two rotating electric vectors have a differentphase when they leave the sample from the value they had initially, so their superpositiongives rise to a plane-polarized beam rotated through an angle Δθ relativeto the plane of the incoming beam. It follows that the angle of optical rotation isproportional to the difference in refractive index, nR − nL. A sample in which these tworefractive indices are different is said to be circularly birefringent.