Optical magnus effect as a consequence of Berry phase anisotropy

Abstract

Presented in this work is a modified geometric optics of smoothly inhomogeneous isotropic medium, which takes into account weak anisotropy introduced by inhomogeneity. Pointed out is the common nature of two fundamental phenomena: Berry’s geometrical phase and the optical Magnus effect, that is, propagation of rays of right and left circular polarization along different trajectories. Shown is that the former phenomenon can be explained by the difference in phase velocity of waves of right-hand and left-hand polarizations, while the latter one is the result of the difference in their group velocity. This work demonstrates that the optical Magnus effect is quite a topological effect that exclusively depends on the geometry of the system’s contour in the momentum space. We predict the effect of the splitting of a ray of mixed polarization into two circularly polarized rays and propose a scheme for the experimental observation of this phenomenon.