Fig. 1. (a) Schematic diagram of the polarization-dependent OT–OS metasurface. (b), (c) Typical unit cell of the OT–OS metasurface with period Px, Py, height H, varying width W, length L (side view), and rotation angle θ along the x−y plane (top view). (d) Phase level of twelve labeled nanobricks, together with (e) corresponding transmittances and polarization conversion efficiencies of the selected nanofins.

Fig. 2. Simulation for the OT–OS metasurface. (a) The entire OT–OS metasurface configuration with top, zoomed, and angled 3D perspective view. (b) Axial section view of the intensity distribution. The dashed lines indicate the focal plane for the function of OT and OS. (c), (d) Transverse section views of the intensity (left column) and phase (right column) distributions at the focal plane of the OS and OT, respectively. The phase profiles are responsible for the transverse fields. White arrows indicate the polarization state.

Fig. 3. Calculated optical forces on a PS particle located in the vicinity of (a), (c) the focusing spot and (b), (d) the vortex field. Longitudinal force as a function of the z position of the particle moving along (a) x=0  μm and (c) 0.4 μm. Transverse forces versus the x position of the particle at (b) z=6.5  μm and (d) 10.4 μm.

Fig. 4. Simulated field distributions for (a) Δf=−3.5  μm and l=1; (b) Δf=6  μm and l=1; (c) Δf=3.5  μm and l=2; (d) Δf=3.5  μm and l=3. Insets show the phase profiles at the focal planes indicated by dashed lines.

Fig. 5. Transmittances (Tx and Ty) and phase shifts (ϕx and ϕy) as a function of the nanobrick size parameters, L and W, and the selected nanobricks have already been labeled.