Reflective plasmonic metasurface and metahologram

Holograms are the optical devices to reconstruct images by recovering amplitude and phase of light, which show many applications in our daily life. Recently, the metasurfaces, an array of sub-wavelength antenna, show the abilities to manipulate both the amplitude and phase of incident electromagnetic wave in a wide electromagnetic region from visible to microwave frequencies. Here, we realized a high-efficiency broadband plasmonic metasurface and metahologram by reflected metasurface made of subwavelength gold nanoantennas which is designed and fabricated in optical frequencies. The reconstructed images of our metahologram show polarization-controlled dual images with high contrast, functioning for both coherent and incoherent light sources within a broad spectral range and under a wide range of incidence angles. Aluminum plasmonics based metaholograms with multi-images, multi-channels, or multiplexing at different wavelengths, on the other hand, prefer narrower plasmonic resonances and less phase levels to realize multi-color metahologram. By combining with the techniques of tunable metasurfaces, metahologram can potentially be used to realize active hologram that works at arbitrary electromagnetic wave region.