Rival research teams are wielding lasers in a battle to develop and perfect 3-D television, an advance likely to make our wide-screen plasmas seem as archaic as old black-and-white sets.
As early computers became faster and more powerful, researchers began thinking about making a compact, inexpensive system to handle real-time holographic displays, said Michael Bove, a holographer at the Spatial Imaging Center at the Massachusetts Institute of Technology’s Media Lab. “We now see a clear path to that [system],” he said. With several research groups actively pursuing the problem from different angles, he said, we may see holographic video in homes within ten years.
In November, a group based at the University of Arizona in Tucson released an update of their work on holographic video, which, unlike the movies now in theaters, doesn’t require a funky-looking pair of glasses to create a full three-dimensional viewing experience.
The group’s advance, published in the November 4 issue of Nature, is all about speed. One of the troubles with real-time holography is displaying frames quickly enough to get a continuous moving image. Normal video flashes 30 frames every second. The Arizona group isn’t quite there yet, having developed a material that can display a new image once every two seconds. But that’s a vast improvement from the four-minute gap that existed only two years ago. The group claims that it’s the first to reach these speeds.
“We need yet another factor of 100 improvement to go to video rate, and it’s our hope that we can do it in another two years,” said Pierre-Alexandre Blanche, the lead author of the study.
To create a hologram, lasers are used to “write” a transparent surface, changing the material’s properties so it scatters light just as if it were reflected off a real object. While the laser’s imprint is usually permanent, the Arizona group’s material — a plastic polymer — can be rewritten quickly enough to give a semblance of movement. After one image is displayed, the next round of laser pulses reorients the polymer’s molecules to produce a different image.
The race to develop high-quality holographic telepresence is causing some tension within the small field of holography. After the University of Arizona team published their work, the holographic firm Zebra Imaging, Inc. — a company with roots in the MIT Spatial Imaging Group and the late, great hologram innovator Stephen Benton — responded with a release that disputed Arizona’s claims to innovation.
The work currently being done at Arizona follows in the footsteps of two of Zebra Imaging’s patented approaches to real-time holographic video, according to Michael Klug, the company’s chief technology officer. Zebra abandoned the approach now taken by Arizona about four years ago because of what Klug described as “fundamental limitations” of the technology, including the high voltage needed to power its lasers.
Despite Zebra’s protests, the University of Arizona group is staying firm on its claim to innovation. “It is sad to see Zebra trying to tarnish our achievements,” said Blanche, who also noted that no one outside of an invitation-only audience at last year’s United Stated Geospatial Intelligence Foundation’s GEOINT conference has seen Zebra’s holographic video. The technology, which is now being marketed to select clients as the trademarked ZScape Motion Display product line, is funded in part by the Pentagon’s Defense Advanced Research Projects Agency.
Because Zebra’s holographic process is covered by a non-disclosure agreement, it is difficult to compare the two competing technologies directly. But from his limited correspondence with Zebra, Arizona’s Blanche believes that the two groups’ approaches are very different.
There are, in fact, a number of other groups and companies working on the same problem — including Holografika, SeeReal, QinetiQ and the University of California, Santa Cruz — each with a unique method. “All the techniques are different and that is what is very interesting in this field: a lot of dynamism, ideas, breakthroughs,” said Blanche.
The basic idea of holographic video is not new. “Arizona did not invent moving holograms, they didn’t invent real-time computation of moving holograms,” said MIT’s Bove. What they did do, he said, is successfully push the properties of a novel material toward video-rate holograms.
But Zebra’s Klug takes issue with the Arizona group’s claim that they are “the first to achieve a speed that can be described as quasi-realtime,” as the Nature study states. His company’s display updates 15 times per second, significantly faster than the University of Arizona’s two-second refresh rate. “I kind of take umbrage to calling that real-time,” said Klug, adding that he expects Zebra’s technology to “prevail” over others.
While the next steps in 3-D entertainment can’t be predicted with confidence, it is clear that the technology’s arrival will be monumental. Over the years, many groups have capitalized on 3-D mania by passing off simpler technologies, like the Pepper’s ghost illusion or digital image fusion, as holograms. But these tricks aren’t nearly as interesting as the real thing, said Bove. Most people, he said, “have never experienced how deep and how natural and how compelling a holographic image can be” — and that will make true video-rate holograms a boon to whoever can perfect them first.