Spin Hall effect of Laguerre-Gaussian beams in PT symmetric metamaterials.

Spin Hall effect (SHE) of Laguerre-Gaussian (LG) beams reflected and transmitted in parity-time (PT) symmetric metamaterials are investigated near the coherent-perfect-absorption (CPA)-laser point and exceptional points (EPs). The numerical results show that large transverse shifts occur at the CPA-laser point regardless of the incident direction. But at EPs, the SHE increases at one side and disappears at the other side, thus achieving the intense SHE of the reflected light beams at the specified side incidence. In addition, it is found that Bragg oscillation can be generated by increasing the period number of PT symmetric metamaterial layers, thus increasing the number of formants in transverse displacement. In particular, the transverse shift peaks of the transmitted beams merge into a positive peak when the incident angle is close to 90 ^∘ and does not change basically with the increasing of Im(ɛ), which can also be considered as a strong tolerance to the variation of Im(ɛ). This feature is expected to realize a new type of optoelectronic devices with anti-interference performance. These results provide a feasible path for the modulation of spin Hall effect of light (SHEL) and provide the possibility for the development of new nanophotonic devices.