Geometrical effect of graded index on the transport of polarized lights

We investigate the geometrical effect of graded index on the transport of polarized lights in the scope of geometrical optics, and present three effective methods based on the Runge-Kutta ray tracing technique in the Frenet-Serret frame and a fixed global Cartesian frame, respectively, for obtaining the polarization state of a polarized light that propagates in graded-index media. The three methods have their own advantages in accuracy, computational efficiency, and difficulty of implementation, respectively. Simulations on a three-dimensional graded-index model show that the results obtained by the three methods are in perfect agreement with each other.