Unusual spin Hall effect of a light beam in chiral metamaterials

We present a solution to the problem of reflection and refraction of a polarized Gaussian beam at the interface between the transparent medium and the chiral metamaterials. Some unusual spin Hall effects of reflected and transmitted light have been found. It is shown that the spin-dependent displacements of the reflected beam centroid can not only reach several tens of wavelengths at certain incident angles; the reversed effect for the transmitted beams can also be realized by tuning the chiral parameters. These findings provide an alternative pathway for controlling the spin Hall effects of light and thereby open up the possibility for developing new nanophotonic devices.