  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 multi-layer
metamaterial holograms where by the nonlinear process of Third Harmonic
Generation, a background free image is formed at a new frequency which is 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 analyzed and prospects for future device applications are
discussed.
