THE FOURTH DIMENSION
Story by Kevin Lollar
PICTURE THIS: a 5-inch disk on which is a frontal view of a woman kneeling in a short robe.
But this is no ordinary picture; the woman is in three dimensions. As the person holding the disk rotates it, the woman rotates too, as if she were in a motion picture front, side, back. She also begins to open the robe, and by the time her back is to the viewer, it’s completely open.
More prurient viewers might keep turning the disk to see whether the woman ever faces forward with the robe open but most people just say, “Wow,” and wonder how it works.
It, of course, is a hologram. Just about everybody has seen one; they’re everywhere on credit cards, billboards, key chains, cereal boxes, toys. The message Princess Leia sends to Obi-Wan Kenobi in “Star Wars” is a hologram; so is the Taung Child skull on the cover of the November 1985 National Geographic.
Simply put, holography reproduces three-dimensional images on two-dimensional surfaces. The easy part is saying what a hologram does. The hard part is explaining how it works.
“It’s a simple, but different way of looking at things,” says Jeff Allen, 41, of EnVision Enterprises in Sausalito. “We sit around and try to describe it, but it’s magic. Gut it’s not a gimmick. It represents where we want to go in communication. A photograph has to be interpreted how deep the subject is, how thick; we have to learn to interpret a photograph. But a hologram is instantaneous information. It gets rid of the barrier of language.”
Holography might be a simple way of looking at things, but explaining how it works is not so simple, so pay attention:
First, a laser beam is split in two. The resulting beams, called the illuminating and reference beams, are then expanded by lenses. The illuminating beam is directed at the subject, say a pistol. When it bounces off the pistol, it collides with the reference beam to form an interference pattern, which contains all the optical information about the pistol, including depth. That information is recorded on film, and the image of the pistol shows up as three-dimensional.
But Allen, who has seven patents to his credit, has bigger holographic fish to fry than 3-D pistols.
With the latest technology, especially Lloyd Cross’ invention of the Multiplex Hologram, holographic motion pictures are now possible the disk with the kneeling woman is a small-scale moving hologram created by Cross. A large-scale holographic movie won’t be one of those campy 1950s flicks that required red and blue glasses to see 3-D images, but a real film with which the viewer really seems to be involved. It is a hologram that includes the fourth dimension time.
Serious research and development in holography has been going on since Hungarian physicist Dennis Gabor made the first hologram in 1947.
Originally, holograms could only be viewed with laser light, but in 1968, Steve Benton created the Benton hologram, which could be seen with sunlight, so-called white light.
Allen was involved in a breakthrough in 1971 when he and Michael Foster came up with a technique that made mass production of holograms financially practical. Two years later, Allen and Foster struck again with the first efficient dichromate gelatin holograms, which greatly improved the ability to see holograms with white light.
Each development has brought holography closer to motion. As early as 1977, Allen produced seven holographic movies for the Japanese market. The next year, the and artist Peter Sparrow produced a series of holographic mini-movies, or live sculptures, featuring actress Jenny Agutter. Allen and Cross are now working on large-scale projected holographic movies.