Figure 3. Nonlinear metamaterial holograms.
Scanning electron microscopy (SEM) images of the first (a) and the second layer (b) of a 3D nonlinear hologram, which projects holographic images of the Hebrew letters Alef and Shin (c) for vertically or horizontally polarized input beams, respectively. (d) Nonlinear holograms of smiley and sad faces for vertically or polarized fundamental beams respectively. (e) SEM image of two typical overlaid layers of nanoantennas. Scale bars, 1 μm (a,b), 200 nm (e).