Stretchable Hologram Has Future in Virtual Reality Applications
Scientists from the University of Pennsylvania have created holograms that can change from one image to another as the materials used to generate them are stretched - another step toward the sci-fi dream of sending and receiving holographic messages. The new method could have applications in virtual reality, flat displays, and optical communications. To make their holograms, the researchers turned to metasurfaces, which are flat, ultra-thin nanostructured surfaces. Previous studies had used these materials to create 3D and multi-color holograms. Using computational models and experiments, the research team calculated how much a holographic image expands as the material generating it stretches, and how far the image plane moves away from its original position. Based on these findings, they created multi-layered holograms made up of two or three different images. As the surface stretches, one image appears in the place of another. For example, a pentagon appears at 340 micrometers away from the film in its relaxed state. Pulling on the material by a certain amount makes a square appear, and stretching it even further replaces the square image with a triangle.