Holograms are undoubtedly spiffy-looking, but they're not exactly cheap; even a basic holographic projector made from off-the-shelf parts can cost thousands of dollars. MIT researchers may have a budget-friendly alternative in the future, though. They've built a glasses-free 3D projector that uses two liquid crystal modulators to angle outgoing light and present different images (eight in the prototype) depending on your point of view. And unlike some 3D systems, the picture should remain relatively vivid -- the technology uses a graphics card's computational power to preserve as much of an image's original information (and therefore its brightness) as possible.
It's not a flawless system, at least not right now. While the modulators work at a speedy 240Hz, the resulting output is just 40Hz. That's fast enough for movies and TV shows, but a far cry from the 60Hz-plus that many regular TV sets can manage. To get wider viewing angles, MIT has also built a special screen using lenticular lenses like those you find in toys and children's books. However, perfection isn't really the point here. So long as the technology keeps advancing, it could lead to projectors with a "good enough" holographic effect that tides people over until real holography is within reach.