longitudinal spin splitting of vortex beam in surface plasmon resonance

The spin-dependent longitudinal splitting of a vortex beam carrying orbital angular momentum is studied in surface plasmon resonance. the existence of orbital angular momentum induces a spatial displacement between the two spin components of the reflected light, which is further enhanced with the excitation of a surface plasmon polariton. by optimizing the structure of the resonance configuration, an optimal condition for enhancing the longitudinal splitting is identified, where it increases to tens of micrometers, which is comparable to the transverse spin hall effect of light in the similar case.