Are we one step closer to the holographic technology found in a galaxy far, far away? (Image credit: Tokyo University)
Remember the scene from Star Wars: A New Hope when Princess Leia used holographic technology to ask Obi-Wan Kenobi for help? That scene is now a reality thanks to a recent breakthrough. Researchers from the Tokyo University of Agriculture and Technology discovered a way to bend light in ways that natural materials can't - using metasurface materials. The result is a true holographic movie.
The holographic movie, inspired by sequential playback of the very first cinematographic projectors of the 19th century, relies on the metasurface, a thin film material just nanometers thick whose microstructure is artificially created in a way to deliver characteristics, like light manipulation, not found in natural materials. Metasurfaces comprise of tiny repeating patterns at scales smaller than the wavelength of light. These metasurfaces can alter the path of light due to their shape and particular arrangement rather than their chemical composition.
To produce a hologram of the Earth rotating, researchers "printed" an array of 48 rectangular frames of a metasurface made of gold. This diffracts laser light shone at it in such a way that it creates a true three-dimensional image appearing mid-air. And unlike popular holograms of celebrities, this one can be viewed from most angles and not lose the illusion. The metasurface frames vary using 48 images of the Earth rotating to get the effect. Each frame was sequentially reconstructed at a rate of 30 frames per second, the frame rate used in most live TV, for movie playback.
The result isn't perfect. The rotation is laggy, and it's a horrendous red color, but it's impressive, especially considering it took an electron-beam lithographic printer six and a half hours to draw 48 frames. Researchers believe a six-minute holographic movie would take over 800 hours to draw. Still, it's a step up from the hologram technology we've seen so far. Researchers will continue to develop the technology to create a full color hologram that's viewable from any angle.
"We're using a helium-neon laser as the light source, which produces a reddish holographic image," said Kentaro Iwami, one of the engineers who developed the system, "so the aim is to develop this to produce full color eventually. And we want it to be viewable from any angle: a 'whole hemisphere' 3-D projection."
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