Brighter, Full-Color Holograms Viewed with Low Light
A 2-D hologram that can be displayed with just a flashlight. Source: University of Utah
Researchers at the University of Utah have created an inexpensive way to create full-color 2-D and 3-D holograms that are far more realistic, brighter and can be viewed at wider angles than current holograms.
The technology could enable a wide range of new applications to be developed for currency and identification badges or amusement park rides and advertisements.
Projection of holograms is generally inefficient because the light we see when it shines on an object is reflected color that bounces back to our eyes, while the rest of the colors in the spectrum are absorbed. This results in a lot of wasted light. Researchers say with a typical LCD projects only 5% or less of the total light is seen.
Researchers found a way to better view holograms by studying how certain butterflies display their colors.
Instead of reflecting only the colors you see while absorbing the rest, all of the white light is redirected so you see the wavelengths of the wing’s color at different locations.
Engineers were able to create holograms using the same theory with algorithms and new fabrication methods that result in much brighter photographic images either in 2-D or 3-D with full, natural colors.
Current full-color holograms require lasers to create and view them. The University of Utah holograms can be viewed with regular white light from any angle. The image details do not change, much like a real object.
"Projecting an image before was very inefficient, and you need a massive lamp," says Rajesh Menon, a researcher at the University of Utah. "Here, you can just do it with just a piece of plastic and a flashlight. It's much simpler and more efficient this way."
Menon says this technology could enable security holograms that produce full-color photographs. It could also be used for identification badges, driver’s licenses and security documents like passports where an officer could use a flashlight to authenticate the document rather than an infrared scanner.
The team has currently produced only 2-D still images with the technology. The next steps will be to create full-color 3-D moving images similar to the chess pieces in “Star Wars.” Doing this could create holograms for use in entertainment such as virtual reality headsets, movie theaters that don’t require powerful projector lamps, or for amusement rides with high-tech special effects. Other uses could include billboards or kiosks with moving 3-D video.
"Imagine going through a ride and you want a monster to jump out. This is a way to do that with much richer color, with higher efficiency and in a much more ubiquitous manner because it's so cheap," Menon says.
The full research can be found in the journal Scientific Reports.
This article was originally published on Globalspec.com.
