Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have designed an ultrathin display that can project dynamic, multicolored holographic images with a wide viewing angle. Key to the new approach is its use of an ultrahigh-capacity, nonperiodic photon sieve. The photon sieve is a thin film of titanium filled with randomly oriented pinholes. By placing the photon sieve close to a transmissive LCD panel, the diffraction angle of the light field can be considerably enhanced. The actual 3D holographic display, and an electron microscope image of the nonperiodic pinholes. Courtesy of KAIST. The system creates images by pointing different-colored, parallel laser beams at a small LCD panel. Each pinhole in the photon sieve corresponds to a pixel in the LCD panel. The pinholes are precisely positioned to correspond to the pixel’s active area. The one-to-one linear relation between the pinholes and the pixels in the LCD panel allows full independent modulation of the light field that is scattered from each pinhole to generate dynamic, 3D holographic images observable from a wide angle. In addition to a wide viewing angle and a large screen size, the flat-panel wavefront modulator provides multicolor projection and a small form factor, opening the potential for viewing holographic displays on thin devices. To create the compact system, the researchers used a 1.8-in. off-the-shelf LCD panel with a resolution of 1024 × 768 pixels. The titanium film, which is attached to the back of the panel, is 300 nm thick. “Our approach suggests that holographic displays could be projected from thin devices, like a cellphone,” said professor YongKeun Park. The team demonstrated its approach by producing a hologram of a moving, tricolored cube. Three-dimensional dynamic color hologram operating at 60 Hz. Courtesy of KAIST. In previous studies, Park’s team used optical diffusors to display dynamic, 3D holographic images; but this device was bulky, difficult to operate, and took a long time to calibrate. In the present work, the team has tailored its photon sieve to demonstrate a simple, compact, scalable method for 3D holographic display that could be applied to existing LCD displays. Improving current holographic display techniques could lead to applications such as 3D cinema viewing without the need for glasses, or the ability to watch holographic videos on television and smartphone screens. The research was published in Nature Communications (https://doi.org/10.1038/s41467-019-09126-9).