New 'Hologram' Device Levitates Particles to Create 3D Objects in Thin Air

From Live Science.com (Jan. 29):

Close your eyes for a moment and picture a hologram. Hold it in your head for a moment, then open your eyes and keep reading.

Ready?

What did the image look like? Here's a guess: A blue, flickering image, projected on thin air, viewable from any angle — a bit like the holograms from the "Star Wars" films. ("Help me Obi-Wan Kenobi! You're my only hope!")

In the real world, though, looking at a hologram isn't so much like looking at a physical object. Lasers need to be used to project the image onto some medium, like a sheet of plastic and glass, which bends and reflects the light so the image appears three dimensional to a viewer. But they work only when the viewer's eye is in a pretty narrow plane of view, almost directly across from the projecting lasers. (HowStuffWorks has a pretty good explanation of this kind of system.)

Now, however, a team of researchers at Brigham Young University has developed a new device that creates truly sculpture-like, three-dimensional images that are sort of like holograms, but on steroids. Projections from their "Optical Trap Display" (OTD), described in a paper published Jan. 24 in the journal Nature, behave a lot more like that image of Princess Leia than any true holograms do.

The OTD takes advantage of a strange technology called the photophoretic optical trap, which allows researchers to levitate a small particle and pilot it through the air. The optical trap hits the particle with a beam of "near invisible" light, the researchers wrote. (The light has a wavelength of 405 nanometers, right at the low edge of what humans can perceive.) [read more]

Interesting. If the researchers can get the glitches out maybe holographic television (or even film) could be possible.