  Pancharatnam-Berry (PB) metasurfaces can be applied to manipulate the phase
and polarization of light within subwavelength thickness. The underlying
mechanism is attributed to the geometric phase originating from the
longitudinal spin of light. Here, we demonstrate a new type of PB geometric
phase derived from the intrinsic transverse spin of guided light. Using
full-wave numerical simulations, we show that the rotation of a metallic nano
bar sitting on a metal substrate can induce a geometric phase covering 2$\pi$
full range for the surface plasmons carrying intrinsic transverse spin.
Specially, the geometric phase is different for the surface plasmons
propagating in opposite directions due to spin-momentum locking. We apply the
geometric phase to design metasurfaces to manipulate the wavefront of surface
plasmons to achieve steering and focusing. Our work provides a new mechanism
for on-chip light manipulations with potential applications in designing
ultra-compact optical devices for imaging and sensing.
