Fig. 1
From: Optical metasurfaces: new generation building blocks for multi-functional optics
Optical Metasurfaces. a Conventional optics (lens) relies on refraction to bend light beams, while a metasurface (b) bends light due to scattering by nanoparticles of different sizes. c, d Multiplexed control of different colors and polarizations by a metasurface. e OM composed of a gold antenna array. The unit cell of the plasmonic interface (yellow) comprises eight gold V-antennas3. f A metalens operating at 660 nm and consisting of TiO2 nanofins on a glass substrate. Scale bar is 300 nm7. g Achromatic metalens with NA ~0.1. Scale bar is 500 nm. The vertical boundary of nanopillars and Babinet structures is visible8. h Fabricated meta-hologram that produces 5 mm large images at a distance of 10 mm. The posts are silicon on SiO29. i SEM image of a dielectric metasurface lens based on Si nanobeams that results in a local Bessel spot focal length of 100 mm at λ = 550 nm10. j DM made from amorphous silicon pillars on a SiO2 that separates x- and y-polarized light and focuses them to two different points11
