University of Arizona (UA) researchers have developed a new type of holographic image that creates a moving, three-dimensional projection without the need for 3D glasses or other special eyewear, says an UA written statement.
The researchers, led by optical sciences professor Nasser Peyghambarian, have made a breakthrough in 3D holographic imaging technology that produces projections comparable in quality to the scene in “Star Wars” where the robot R2D2 projects a three-dimensional image of Princess Leia (Carrie Fisher) making a plea for help. What used to be science fiction is now close to becoming reality, the UA statement says.
The 3D technology is likely to have applications in telemedicine, advertising, cartography and entertainment. “Holographic telepresence means we can record a three-dimensional image in one location and show it in another location, in real-time, anywhere in the world,” Peyghambarian said.
The process starts by recording an object using an array of regular cameras, each of which views the object from a different perspective; the more cameras used, the more refined the holographic presentation appears.
However, what makes the system work is a screen made from a photorefractive material capable of refreshing holograms every two seconds, said Pierre-Alexandre, an assistant research professor at UA. The material is able to achieve a speed that can be described as quasi-real-time, he said.
The information recorded by the cameras is encoded onto a fast-pulsed laser beam, which interferes with another beam that serves as a reference. The resulting interference pattern is written into the photorefractive polymer, creating and storing the image. Each laser pulse records an individual holographic pixel, or “hogel", in the polymer. A hogel is the three-dimensional version of a pixel, the basic units that make up the picture.
The hologram fades away by natural dark decay after a couple of minutes or seconds depending on experimental parameters, or it can be erased by recording a new 3D image, creating a new diffraction structure and deleting the old pattern, Peyghambarian said.
The 3D holographic imaging technology is the result of collaboration by UA and Nitto Denko Technical, or NDT, an Oceanside, Calif. company. NDT provided the polymer sample and media preparation. “We have made major advances in photorefractive polymer film fabrication that allow for the very interesting 3D images obtained,” said Michiharu Yamamoto, vice president at NDT.
The prototype device uses a 10-inch screen, but Peyghambarian's group is already successfully testing a much larger version with a 17-inch screen. In addition, the current telepresence system can present in one color only, but multi-color 3D display devices capable of writing images at a faster refresh rate that approach the smooth transition of images on a television screen, have been demonstrated. Those devices could be incorporated into a telepresence system, the researchers say.