Vectorial Wavefront Manipulations Based on Misalignment Resilient Cascaded Metasurfaces

Due to spatial symmetry constraints, existing single-layer metasurface schemes suffer from reduced parallel control capabilities and information capacity in their Jones matrices. Recently, bilayer metasurface strategies have enabled significant enhancements in polarization and nonreciprocal modulations, facilitating applications in holographic display and optical communications. However, a more intuitive Jones matrix analysis is needed, and the current pixel-wise design of bilayer metasurfaces necessitates precise nanofabrication and alignment, leading to increased costs and technical challenges. In this paper, cascade metasurfaces design strategies for vectorial wavefront manipulations with misalignment robustness are investigated. First, an intuitive visualization method for the Jones matrix is established, based on the analysis of polarization eigenstates, polarization dichroism, and phase modulations. On this basis, a pixel-wise design approach of cascaded metasurfaces aimed at sophisticated vectorial spatial light modulation is proposed. This approach achieves assembly tolerances more than one order of magnitude higher than those of the control group, by employing a specialized spatial frequency optimization. Specifically, both the cascaded and individual metasurfaces are predesigned to serve distinct functions. Multichannel vectorial wavefront multiplexing and polarization encryption are all realized. It is believed that the work offers valuable insights into sophisticated polarization modulation techniques and the cost-effective design of multilayer metasurfaces.