On-chip spin-Hall nanograting for simultaneously detecting phase and polarization singularities

A plasmonic spin-Hall nanograting structure that simultaneously detects both the polarization and phase singularities of the incident beam is reported. The nanograting is symmetry-breaking with different periods for the upper and lower parts, which enables the unidirectional excitation of the SPP depending on the topological charge of the incident beam. Additionally, spin-Hall meta-slits are integrated onto the grating so that the structure has a chiral response for polarization detection.