  The spin-dependent routing of surface plasmons on metal by use of mirror
symmetric periodic metasurface is presented and analyzed. We incorporate the
intrinsic transverse spin angular momentum of the plasmonic wave in order to
efficiently couple the incident light carrying circular polarization to a
desired direction. The combination of the oblique incidence of polarized light
with the accurately designed momentum matching properties of the grating
provides a perfect way to achieve a spin-locking metasurface that routes the
plasmonic beams.
