Light angular momentum flux and forces in birefringent inhomogeneous media

The angular momentum carried by a monochromatic optical field is separated into an orbital and a spin part beyond the paraxial approximation. These quantities have been distinguished on the grounds of the different mechanical effects they produce in transparent and birefringent media endowed with internal degrees of freedom. The orbital and the spin angular momentum flux densities exhibited are shown to be divergence free in homogeneous and isotropic media and to give back the correct expressions in the paraxial limit.