Metasurface-integrated silicon nitride waveguides for holography with full polarization control.

Here, a silicon-based metasurface integrated on a silicon nitride (SiNx) waveguide is proposed, enabling continuous control of light's phase and polarization. By utilizing resonant phase, geometric phase, and detour phase with fixed inter-unit spacing, the metasurface achieves full phase coverage under arbitrary polarization states while reducing design complexity. We demonstrate hologram images of letters under four polarization states: x-, y-, right circular, and left elliptical polarizations, achieving phase control with the same amplitude in corresponding polarizations. The results provide more possibilities for generating complex free space light fields via on-chip devices.