A Stanford University student, working with colleagues from Stanford, IBM Corp’s Almaden Research Center and SDL Inc has made what appears to be a breakthrough in generating three-dimensional images. Over the years researchers have developed a number of ways to produce three-dimensional images. The simplest is to use stereo pairs of images that show slightly different perspectives presented independently to each eye. The technique used by graduate student Elizabeth Downing, studying with Stanford electrical engineering Professor Lambertus Hesselink was first attempted during the 1970s by a group at Battelle Memorial institute in Columbus without success, due to the lack of semiconductor lasers or the variety of fluorescent glass. Ms Downing said the technology was unlike virtual reality, where the users need to wear special equipment on their heads. The San Jose, California team’s prototype is a collection of lasers and mirrors about the size of a microwave oven, which draws rings of light within a chunk of green-tinged glass as big as a sugar cube, to which Erbium, Praseodymium and Thulium elements have been added. The images can be viewed with the naked eye from any direction. When beams that are shone from two infra-red lasers into the cube intersect, the elements trapped within the glass react to give off light in various shades of red, blue or green. By altering the direction of the laser, various moving images can be drawn. Due to the image’s translucent quality, which assumes a ghostly appearance, its unlikely that the technology could replace a conventional television screen. Another potential drawback for some uses is that it takes about 500 times as much data to construct a three-dimensional object as it does to draw the same object in two dimensions. But for some applications, like medical imaging or scientific simulation, the translucent image could prove to be a real benefit. The Almaden Research Center helped to identify the right glasses to create the three different colors needed, and the US Navy provided Ms Downing with her initial funding in the form of a $350,000 grant in 1993. Her team subsequently received additional support from the Advanced Research Projects Agency at the Department of Defense through Stanford’s Center for Nonlinear Optical Materials. But by the time she was ready to build a prototype with much smaller semiconductor lasers, there was little in the way of finances left. The team turned to SDL for help, and the company provided the much needed equipment and technical advice. Now the problem that will face 3D Technology Laboratories Inc, formed to develop the system, is how, or rather to whom, to market it. Ms Downing, currently working for a doctorate in engineering, hopes to refine and enlarge the technology to produce three-dimensional images of brains for teams of doctors, more realistic displays for air traffic control – and perhaps to incorporate the technique into video games.
