Imagine sitting in your office or at home and suddenly seeing the wall in front of you disappear. Behind it is another office with people at a table, and you’re at the table. Or the scene that materializes is another living room on a different continent, and you’re there visiting with friends and family.
The technology behind these intriguing, if somewhat eerie, scenes is holographic videoconferencing, for which a working prototype already exists at Massachusetts Institute of Technology. In-office/in-home use is at least 10 years down the road, however, according to Stephen Benton, head of MIT’s Spatial Imaging Group at the Media Laboratory.
“In the last few years, our research has brought us to the point where television was in 1926,” Benton said. “Our main job is to show that we can do it. Ten years ago, people thought we were crazy.”
But the researchers can now show some convincing, if not quite tangible, proof that they aren’t crazy. And you won’t have to wait a couple of decades before the first manifestations of the technology move out of the laboratories and into the real world.
Thanks to fiber-optic technology, for example, holographic data storage is becoming a practical reality.
“We can store 100,000 different photos or digital pages – that’s a terabyte [of information] – in something the size of a sugar cube,” Benton said.
Fiber optics can easily handle the wide bandwidth that holograms require because the signals are much wider than those used for television. And even better, the newer technology transmits information more rapidly.
Various industrial applications are being used to take advantage of holographic technology for quality control in manufacturing and testing for fractures, such as holographic non-destructive testing. The flexibility of the technology makes other industrial design applications inevitable.
Holograms or “heads-up” displays are used in military and civilian aircraft. Holograms give pilots critical information as they look through their cockpit windows.
The technology has found a home in the less-technological world, too. In an effort to convey images and messages not possible with traditional media, artists “explore” 3-D space and pure light via holography.
But medical professionals are the most likely early users of improved holograms. Today’s X-raying methods of Magnetic Resonance Imaging and CAT scan cameras gather 3-D data, but holography offers a way to examine those images in a full 3-D format. Parallax, available only with holograms, allows viewers to manipulate the image and see different perspectives as if the object were actually there. The bonus is that because the complex images will be more vivid, they will be more accurately interpretable by physicians.
Improving the technology that produces holograms is only half of the equation. You need to be able to view them, so work on display media and devices such as holovideo is keeping pace with evolving holographic technology. Benton already has two working prototypes of a real-time imaging system that can render and display computer-generated holograms at video rates. In designing the electronic video display, researchers have established the principles of information reduction and image scanning. Scaling up to practical display sizes still poses significant electronic and electro-optical challenges. So far, the parallelization of the computation, storage and display is feasible for three by five inch images.
Several groups around the world are focused on using LCD screen technology. One group in England is working to shorten the transmission time needed for holographic images.
“Another group is working on images you can feel,” according to Benton. “You use a pointer-like tool on the image and it ‘feels’ like you’re pushing it. Eventually, the images should be able to talk, too.”
The next major breakthrough in optical devices is imminent, said Benton. “Between 1926 and 1936, television went from mechanical technology to electronic, and that’s next for holography,” he said.
Researchers are betting that the electronic key to practical holographic devices rests with Micro Electro Mechanical Systems (MEMS), the integration of mechanical elements, sensors, actuators and electronics on a common silicon substrate. The realization of complete systems-on-a-chip is the result of the combination of silicon-based microelectronics and micromachining technology.
With MEMS, the cost of producing optical devices will drop. “The first prototype was a big chunk of a million dollars,” said Benton. “The first [more reasonable] ones will be about $100,000 and work their way down” in price.
But don’t expect to see Star Wars-like holograms, the ones that seem to float in space, soon. “Those have a serious problem with physics,” said Benton.
On the other hand, don’t be surprised if five years from now holographic technology is no longer just a curiosity and has made real inroads into practical life.