Fig. 2: Design of a metasurface for a vectorial metahologram

a, b Schematic of unit cell and metamolecule of the metasurface. The rectangular silicon pillar in a unit cell is on a sapphire substrate. Each subwavelength metamolecule comprises four unit cells to modulate the phases and amplitudes of LCP (“L”) and RCP (“R”) incident light to generate arbitrary vectorial polarization distribution on the metasurface or the hologram plane. The period \((P)\) and dimensions \(\left(h,\,l,\,d\right)\,\) of a unit cell are \((350,\,350,\,240,\,135)\) nm. c Calculated CPCR of different unit cells for LCP to RCP conversion. The optimal parameters are marked by the yellow star, with the transmittance of 75% under the 808 nm LCP incidence. d, e Scanning electron microscopy images of the fabricated metasurface