Researchers have created inexpensive, full-color, 2D and 3D holograms that are more realistic and brighter, and can be viewed at wider angles than current holograms.
Typically, the projection of any image, whether it is two- or three-dimensional, is inefficient because when white light shines on an object, only the reflected color that bounces back can be seen by the eyes, while the rest of the colors of the spectrum are absorbed. Therefore, there is a lot of wasted light. With a typical LCD projector, for example, only 5 percent of the total light may be seen at one time.
The new technology borrows from the same principle behind how wings of certain butterflies display their colors — instead of reflecting only the colors that are seen, while absorbing the rest, all of the white light is redirected so the wavelengths of the wing's colors at different locations are seen. None of the light is absorbed and therefore wasted.
Using algorithms and a new fabrication method, the researchers created holograms that do the same thing — redirect colors to appropriate locations instead of absorbing most of it — to project much brighter photographic images either in 2D or 3D and with full, natural colors. Currently, full-color holograms require lasers to not only make them, but also to view them. The new holograms can be viewed with regular white light. Most importantly, these holograms can be viewed from any angle, and the image detail does not change, much like a real object.
Such technology could be used on currency notes with security holograms that produce more lifelike images. Currently, the holograms on some foreign currency or on credit cards look like shimmering monochromatic images, but the new holograms would be more like full-color photographs. It also could be used for identification badges, driver's licenses, and security documents like passports. An officer could use just a flashlight to authenticate the document instead of a special light such as an infrared scanner. The holograms could be inexpensive to manufacture because each sticker could be stamped out like a compact disc or DVD.
While only 2D still images have been produced with the technology so far, researchers believe it would not be difficult to take the next step to create full-color, 3D moving images. Those holograms could be utilized in entertainment such as for virtual reality headsets, for movie theaters that wouldn't require powerful projector lamps (and it could be an avenue for 3D movies without glasses), or for amusement rides that use high-tech special effects.