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.

No abstract

In the spin Hall effect of light (SHEL) with an incident linear polarization, the left circularly polarized (LCP) and the right circularly polarized (RCP) spin components are transversely shifted to opposite sides of the incident plane. We find that each spin component of the reflected or the refracted light is actually the coherent superposition of a pair with the same handedness. The two parts in a pair are generated by both the incident LCP and RCP components, respectively, and have different transverse shifts. Their weighted shifts lead to the overall displacement of the corresponding spin component. This perspective can successfully elucidate the dependence of the SHEL spin separations on the angle of polarization of the incident electric field.

We propose and realize a simple technique to measure the tiny spin Hall effect of light from the ratio of the minimum and the maximum intensities along two cross-polarization directions, without the requirement of a position-sensitive detector in the conventional weak measurement. Furthermore, the weak intensity ratio is dramatically amplified by purposely choosing the intensity along the direction close to that of the minimum instead of the maximum along the perpendicular polarization direction, which is verified by the experimental results. In principle, this method also can be modified for measurement of the high extinction ratio of a polarizer.