Fig. 1. Basic structure diagram of LCPG

Fig. 2. （a）Molecular arrangement of liquid crystal without applied voltage；（b）Molecular arrangement diagram of liquid crystal under applied voltage.

Fig. 3. Schematic diagram of oblique incidence of light beam in cascaded liquid crystal polarization gratings

Fig. 4. Three-dimensional coordinate diagram of LC director and incident beam vector

Fig. 5. Relationship between liquid crystal molecular tilt angle and voltage

Fig. 6. Internal structure diagram of liquid crystal variable retarder under oblique incidence

Fig. 7. Schematic diagram of oblique incident beam refraction in liquid crystal variable retarder

Fig. 8. Relationship between oblique incident angle，vol‑tage and retardation.

Fig. 9. Relationship between oblique incidence angle and ellipticity

Fig. 10. Relationship between ellipticity of incident light and diffraction efficiency

Fig. 11. Relationship between oblique incident angle，ellipticity and diffraction efficiency.

Fig. 12. （a）Schematic diagram of experiment；（b）Diagram of experimental device.

Fig. 13. Relationship between oblique incident angle，voltage and retardation.

Fig. 14. （a）Schematic diagram of experiment；（b）Diagram of experimental device.

Fig. 15. Relationship between oblique incidence angle and ellipticity

Fig. 16. （a）Light spot pattern at 45° ellipticity；（b）Light spot pattern at 15° ellipticity；（c）Light spot pattern at 0° ellipticity.

Fig. 17. （a）Schematic diagram of experiment；（b）Diagram of experimental device.

Fig. 18. （a）Light spot pattern at 0° incidence；（b）Light spot pattern at 5° incidence；（c）Light spot pattern at 10° incidence.

Fig. 19. （a）Schematic diagram of experiment；（b）Diagram of experimental device.

Fig. 20. Relationship between oblique incidence angle and optimal operating voltage of LCVR

Fig. 21. （a）Spot diagram before voltage optimization；（b）Spot diagram after voltage optimization.

Fig. 22. Diffraction efficiency diagram of cascade system with different steering angles before and after voltage optimization