Fig. 1. Schematic diagram of proximity stepper holographic interference splicing exposure. （a） Schematic diagram of the exposure system； （b） Photo of the exposure system； （c） Step-by-step exposure route map.

Fig. 2. Relationship between the splicing seam width and z， which means the distance between the mask and the exposure substrate. （a） Two-dimensional polarization distribution of the interference light field at the exposure plane； （b） Relationship between the splicing seam width and z.

Fig. 3. Fabrication of large-aperture liquid crystal polarization grating. （a） Relationship between diffraction efficiencies at various diffraction orders and the number of liquid crystal spinning-coated layers for the large-aperture LCPG； （b） Fabricated large-aperture liquid crystal polarization grating.

Fig. 4. Micro-structure of the large-aperture liquid crystal polarization grating. （a） Grating structure within a single exposure region； （b） Micro-structure at the splicing seam.

Fig. 5. Simulation and experiment of far-field diffraction of the large-aperture liquid crystal polarization grating. （a） Far-field diffraction efficiency simulation； （b） Far-field diffraction pattern simulation； （c） Far-field diffraction pattern experiment.