Ordinary and extraordinary rays in gradient-index lenses

We assume that the polarization modes of a gradient-index medium with circular cylindrical symmetry are radial and tangential. Making use of a ray-optics method developed for anisotropic crystals, we relate the polarization modes with the permittivity and the dielectric tensor constant of the medium. The polarized imaging response of gradient-index lenses is used to associate ordinary rays with the tangential mode and extraordinary rays with the radial mode. The polarization-mode description is in agreement with the experimental results here. These experimental results allow extending the mode description developed for meridional rays to include skew rays. (C) 2003 Optical Society of America.