Singular polarization eigenstates in anisotropic stratified structures

A new optical element that displays singular polarization eigenstates is proposed. It consists of a planar stratified structure composed of alternate gyrotropic and birefringent layers. The orthogonality of the polarization eigenstates is lost because of anisotropic reflections at the interfaces, which are enhanced by the special condition chosen for the multiple-beam interference. First we show that the anisotropic reflection at the interface between the layers with linear and circular symmetries does produce strong enough dichroism to break the orthogonality of polarization eigenstates. Second, we investigate the behavior of these eigenstates with respect to their linearity and orthogonality as a function of the width of the layers. Our results concretely demonstrate that it is possible to control the effective optical parameters of such stratified structures by adjusting the thickness of each anisotropic layer. Finally, we obtain the necessary conditions for designing a double-layer system with singular eigenstates of linear polarization.