Impact of in-plane spread of wave vectors on spin Hall effect of light around Brewster's angle

We theoretically and experimentally demonstrate that displacements induced by the spin Hall effect of light are determined by not only the out-plane but also the in-plane spreads of wave vectors when a P-polarized Gaussian beam reflected from an air-glass interface around the Brewster's angle. The decisive impacts of the wave vector spreads are manifested in the dramatic changes of the reflected light intensity distribution when the polarization or the incident angle of the incident beam slightly varies. The experimental displacement data agree well with the theoretical prediction by taking into account of the in-plane spread of wave-vectors.