Over the past few decades, engineers have developed various devices that can create holograms, three-dimensional (3D) or two-dimensional (2D) images produced by precisely controlling the shape and direction of traveling light waves. Holograms are now widely used to produce visual representations of objects and to measure their physical properties, authenticate documents or bank cards, and serve as visualization tools in some educational settings.
While the quality of the holograms that can be produced has improved significantly in recent years, most existing technologies can generate only one hologram at a time. To simultaneously generate several independent holograms, one would need to increase a device’s so-called holographic channels (i.e., separate streams of independently controlled holograms), which tends to reduce the quality of the produced images or the speed at which they can be refreshed.
Researchers at Southeast University in China recently developed a new programmable metasurface, an engineered ultrathin material that can manipulate waves in unique ways, which reliably generates dozens of holograms at once. This metasurface, introduced in a paper published in Nature Electronics, consists of 6,000 elements that can be individually controlled, both in terms of their spatial arrangement and how they change over time.
