MIT Researchers Create Colorful Holographic TVs on the Cheap (Video)

Want to watch TV in 3D? You may be in luck. MIT researchers have figured out a way to generate colorful holograms that are much cheaper than standard displays. The findings could eventually lead to color holographic-video displays that are less costly to manufacture than today's experimental, monochromatic display.

When light strikes an object with an irregular surface, it bounces off at a huge variety of angles. This causes us to see different aspects of the object when we view it from different perspectives. Holograms work in much the same way. A beam of light passes through a so-called diffraction fringe, which bends the light so that it, too, emerges at a host of different angles.

There are several different ways to produce holographic video. One is to create diffraction fringes from patterns displayed on an otherwise transparent screen. The issue with this particular technique, though, is that the pixels of the diffraction pattern have to be as small as the wavelength of the light they're bending. Unfortunately, most display technologies simply aren't small enough.

The second technique is more widely used. Called acousto-optic modulation, this method involves precisely engineered sound waves that are sent through a piece of transparent material. These sound waves essentially squeeze and stretch the material, and they change its index of refraction. If you shine a laser through it, the waves diffract it.

Previous renditions of acousto-optic modulation involved using a crystal of an expensive material called tellurium dioxide. In fact, it was the biggest piece of crystal that had ever been grown, and it was unfortunately not TV resolution. Yet in this new work, the researchers used a much smaller crystal of a material called lithium niobate. Beneath this crystal, the researchers created microscopic channels known as waveguides, which confine the light traveling through them. Onto each waveguide is a metal electrode, which can produce an acoustic wave.

The result is a chip that can be used in a color holographic-video display whose resolution is roughly that of a standard-definition TV and which can update images 30 times a second--fast enough to produce the illusion of motion. Best of all, the chip itself only costs about $10 to make, which is a massive reduction of costs and actually makes the whole system feasible in manufacturing.

Some researchers, though, think other parts are more exciting. "What's most exciting about [the new chip] is that it's a waveguide-based platform, which is a major departure from every other type of spatial light modulator used for holographic video right now," said Daniel Smalley, a graduate student in MIT's Media Lab, in a news release.

The details of the new technology are published in the journal Nature.

Want to learn about previous work that MIT has done with holograms? Check out the video below, courtesy of YouTube.