Fig. 1. (a) Experimental light path diagram; (b) interference angle variation diagram of exposure surface; (c) sample rotation angle diagram; (d) theoretical simulation diagram of 2D variable spacing grating

Fig. 2. Microstructural diagrams of polymer and liquid crystal separation at different exposure time. (a) 2 s/60 s; (b) 4 s/60 s; (c) 5 s/60 s

Fig. 3. Skew coordinate diagram of 2D variable spacing grating

Fig. 4. Device diagram of period measurement

Fig. 5. Diffraction spot maps at (a) diagonal upper left corner area, (b) diagonal center area, (c) diagonal lower right corner area, (d) off-diagonal area; atomic force microscope micro structure maps of grating at (e) diagonal upper left corner area, (f) diagonal center area, (g) diagonal lower right corner area, (h) off-diagonal area

Fig. 6. Diffraction spots (a) without and (b) with applied voltage

Fig. 7. First-order diffraction efficiency and zero-order diffraction efficiency as functions of applied external voltage

Fig. 8. (a) Periodic variation curves at different D; (b) periodic variation curves at different f; (c) periodic variation curves at different α