Fig. 1. Diagram of generalized Snell's law^[56]

Fig. 2. Gradient phase metasurfaces. (a) Gradient phase metasurfaces based on V-shaped metal antennas^[56]; (b) high-efficiency gradient phase metasurfaces with metal-dielectric-metal configuration^[50]; (c) broadband high-efficiency gradient phase metasurfaces based on trapezoidal metal structures^[66]; (d) gradient phase metasurfaces based on dielectric materials^[61]

Fig. 3. Physics requirement for perfect anomalous reflection^[58]. (a) Schematic of perfect anomalous deflection, arbitrary beam steering can be achieved by the modulation of metasurface; (b) phase requirement of metasurface at different spatial positions under the condition of different deflection angles; (c) amplitude requirement of metasurface at different spatial positions under the condition of different deflection angles

Fig. 4. Phase-amplitude coordinated anomalous reflection metasurfaces. (a) Non-local metasurfaces based on rectangular metal patches^[67]; (b) dielectric non-local metasufaces based on topology optimization^[70]; (c) multi-functional non-local metasurfaces based on q-BIC^[75]

Fig. 5. Perfect anomalous reflector based on the Q3D-SWS^[55]. (a) Schematic of Q3D-SWS; (b) comparison with published works; (c) SEM side-view image and cross-section image of the sample; (d) broadband spectra measured in the experiment and calculated in the design

Fig. 6. Schematic of beam steering systems based on anomalous deflection metasurfaces. (a)(b) Anomalous deflection metasurfaces beam steering systems based on TCO materials^[76-77]; (c) (d) anomalous deflection metasurfaces beam steering systems based on liquid crystals^[78-79]; (e) anomalous deflection metasurfaces beam steering system based on MQWs^[80]; (f) anomalous deflection metasurfaces beam steering systems based on MEMS^[81]; (g) anomalous deflection metasurfaces beam steering systems based on phase-change materials^[82]

Fig. 7. Schematic of metalens based on anomalous deflection metasurfaces. (a) Large numerical aperture metalens based on anomalous deflection^[42]; (b) hybrid metalens based on anomalous deflection^[40]

Fig. 8. Schematic of splitters based on anomalous deflection metasurfaces. (a) Wavelength-dependent beam splitter based on anomalous deflection metasurfaces^[90]; (b) polarization-dependent beam splitter based on anomalous deflection metasurfaces^[91]; (c) power-dependent beam splitter based on anomalous deflection metasurfaces^[92]

Fig. 9. Schematic of meta-robots based on anomalous deflection metasurfaces. (a) Self-stabilizing optical levitation device based on anomalous deflection metasurfaces^[93]; (b) microscopic meta-vehicle powered and steered by embedded anomalous deflection metasurfaces^[94]

Fig. 10. Schematic of a spectrometer based on anomalous deflection metasurfaces^[88-89]

Fig. 11. Schematic of AR systems based on anomalous deflection metasurfaces. (a) Stereo display based on polarization multiplexed metasurface grating waveguides^[83]; (b) full-color augmented reality waveguide glasses based on metasurface grating^[84]

Fig. 12. Schematic of integrated light sources based on anomalous deflection metasurfaces. (a) External cavity laser based on anomalous deflection metasurfaces^[85]; (b) VCSEL directional emission based on anomalous deflection metasurfaces^[86]; (c) LED directional emission based on anomalous deflection metasurfaces^[87]

Fig. 13. Schematic of sensors based on anomalous deflection metasurfaces. (a) Optoelectronic detection enhancement based on anomalous deflection metasurfaces^[95]; (b) enhancement of AFM detection sensitivity based on anomalous deflection metasurfaces^[44]