Figure 1

Schematic diagram of the experimental setup to generate optical illusions. A polarizer and a quarter-wave plate are used to generate the incident light with required polarization states. Upon the illumination of linearly polarized light at normal incidence, an optical illusion is perceived on the viewing screen. The top-left inset shows a single pixel of the reflective metasurface, which consists of gold nanorods on the top, a SiO₂ layer in the middle and a gold layer at the bottom. Under the illumination of RCP and LCP, the ‘Rubin’s face’ (bottom right) is projected onto the left and right side of the image plane, respectively. The ‘vase’ (optical illusion) is perceived between the two separated “Rubin’s faces” during the visual perception.