Publishing their results in Nature Communications under the title “Ultrathin wide-angle large-area digital 3D holographic display using a non-periodic photon sieve”, the researchers used the 1024×768 pixels of the transmissive LCD to modulate the incident wavefront of a coherent laser beam at speeds up to 60Hz. The photon sieve stacked to the LCD consisted in a non-periodic distribution of randomly oriented pinholes in a titanium-coated silica plate. The pinholes in the photon sieve were 2.2μm in diametre, and distributed at a ratio of one pinhole for each LCD pixel, allowing full independent modulation of the light field scattered from each pinhole to generate the dynamic holographic images.
Because the pinholes only let minimal amounts of light through diffraction, it took differently coloured laser beams collimated at the small LCD panel to get enough diffracted light out and produce the animated holograms.
“Our approach suggests that holographic displays could be projected from thin devices, like a cell phone,” says Professor YongKeun Park, a physicist at KAIST who led the research.