Remember the first time you saw a 3D movie, the images popping out of the screen and looking so cool that you forgot for a moment that you were wearing those annoying (and unsightly) glasses? Imagine if you could experience 3D video in the comfort of your home sans dorky specs.

That possibility may be closer than you think, thanks to the work of MIT’s CELab (cel.media.mit.edu). Researchers are developing a system called Mark III, a third-generation holographic video display that will be small enough to sit on a desk or be added to an entertainment center. And with a cost of only a few hundred dollars, the system should be within the price range of most consumers.

The team, led by CELab director V. Michael Bove Jr., used some aspects of the lab’s previous large and expensive holographic display systems but made some key modifications. Mark III uses a standard PC graphics processor for 3D image processing, a redesigned acousto-optic modulator to direct the laser light that produces the hologram, and fewer, more efficient mirrors and lenses.

The system creates a holographic video by using software to create a real-time 3D model. That model determines the light diffraction pattern needed to create a corresponding holographic image. When the video signal runs through the light modulator, it creates a light wave consisting of varying intensities and frequencies that, when projected on an opaque screen, results in a hologram.

“We thought that making it inexpensive would be hard, but that’s not nearly so much a challenge as making the box relatively shallow,” says Bove. “People are now used to flat panel displays, and this system is shaped more like a CRT in that that there needs to be significant depth behind the screen.”

Although the nearly completed Mark III system only renders monochromatic holograms about 3 cubic inches, the team is already envisioning the Mark IV, which will be capable of full-color, desktop-monitor-sized holograms. Bove believes that this system could be available within five years and retail between $200 and $500.

Taking Silicon Chips For A Spin

The quest for faster, smaller computer chips has led some researchers down the path of spintronics, or utilizing the spin (up or down) of electrons, in addition to their magnetic charge, to process more information. The trick in accomplishing this lies in measuring the spin direction of the electrons. While metallic spintronic devices use light to do this, silicon doesn’t allow that kind of measurement.

“Since silicon is the material basis for modern computing circuits, it is therefore clear that the fundamentals of spin injection, transport, and detection must be demonstrated in silicon for spintronics to have a viable future,” says Ian Appelbaum, an assistant professor in the Electrical Computing and Engineering Department at the University of Delaware who has recently created the first silicon-based spintronic device.

Appelbaum’s research team accomplished this feat by creating a spin detector comprising three layers: nickel-iron, copper, and a silicon substrate. Electrons are injected through a 10-micrometer-thick layer of silicon, which lies on top of the detector. As the electrons pass through the injector, the spin-down electrons are filtered out, leaving only the spin-up electrons to pass through the silicon layer into the detector. The detector is then able to change its field magnetism; if it remains positive, then the electrons continue to pass through to the silicon substrate, creating a small charge. If the detector flips its field magnetism to negative, no current is created.

The research is just a first step in creating a useful silicon spintronics device; the team is working next to improve the spin polarization and output current (which is currently measured in picoamperes—too small to be useful). Additionally, fabricating the detector is complex and incompatible with current silicon fabrication techniques. But Appelbaum believes that his research could result in a silicon-based spintronics chip in the next 10 to 20 years.