Nonlinear metamaterials for holography

A hologram is an optical element storing phase and possibly amplitude information enabling the reconstruction of a three-dimensional image of an object by illumination and scattering of a coherent beam of light, and the image is generated at the same wavelength as the input laser beam. In recent years, it was shown that information can be stored in nanometric antennas giving rise to ultrathin components. Here we demonstrate nonlinear multilayer metamaterial holograms. A background free image is formed at a new frequency—the third harmonic of the illuminating beam. Using e-beam lithography of multilayer plasmonic nanoantennas, we fabricate polarization-sensitive nonlinear elements such as blazed gratings, lenses and other computer-generated holograms. These holograms are analysed and prospects for future device applications are discussed. Phased metasurfaces have been extended to the nonlinear regime, enabling coherent generation, beam steering and lensing of light beams in one thin element. Here, Almeida et al . demonstrate a nonlinear multilayer metamaterial hologram generating images at the third harmonic frequency of the illuminating beam.