Fig. 1. Schematic diagram of the multifunctional metasurface image display enabled by merging spatial frequency multiplexing and near- and far-field multiplexing

Fig. 2. Unit-cell structure and optical manipulation principle of the multifunctional metasurface. (a) Illustration of the nanostructure unit-cell; (b) The relationship between geometric phase delay and the orientation angle of the nanobrick; (c) The relationship between the output intensity and the orientation angle of the nanobrick

Fig. 3. Observation characteristics of the human eye and an example of spatial frequency multiplexing. (a) Illustration of the human eye's observation of a sine wave image; (b) Contrast sensitive functions; (c) Image P₁; (d) Image P₂; (e) Merged image P_i generated bycombining the high-frequency part of P₁ and the low-frequency part of P₂

Fig. 4. Design flow chart and optimization results of the multifunctional metasurface. (a) Design flow chart of the multifunctional metasurface; (b) The final optimized orientation distribution of the multifunctional metasurface; (c) Simulated reflectivity of the cross-polarized and co-polarized parts under a normal circularly polarized light incidence; (d-g) The relationship between the total phase delay and the orientation angle of the nanobrick at different wavelengths

Fig. 5. SOI metasurface sample fabrication process and localized SEM image of the sample. (a) SOI metasurface sample fabrication process; (b) Partial scanning electron microscope image of the sample

Fig. 6. Experimental setups of the multifunctional metasurface. (a) General sketch and detailed illustration of the microscope to observe the grayscale nanoprinting image in the near-field; (b) The experimental setup to observe the holographic image in the far-field

Fig. 7. Experimentally captured nanoprinting images in the near-field. (a) Experimental nanoprinting image under white light illumination; (b-e) Experimental nanoprinting images at different wavelengths

Fig. 8. Design and experimental results of holographic images in the far-field. (a) Designed holographic image; (b-e) Experimentally captured holographic images at different wavelengths; (f) High spatial frequency components of the designed image; (g-j) High spatial frequency components of experimentally captured holographic images at different wavelengths; (k) Low spatial frequency component of the designed image; (l-o) Low spatial frequency components of experimentally captured holographic images at different wavelengths