New approach yields bigger and better holographic displays
Current holographic technologies are nowhere near capable of producing realistic, life-size projections that maintain quality from an array of viewing angles like those portrayed in movies like Star Wars. But things are moving in the right direction with researchers having developed a new type of 3D dynamic holographic display that they claim performs 2,600 times better than existing technologies.
One key limitation to current holographic display technology is that, despite two-dimensional display technologies with tens of millions of pixels, it takes a lot more information than is contained in all those megapixels to generate a sizable 3D image. Using existing display and wavefront modulator technology, which is an optical manipulation device that controls the direction of the light, a tiny hologram about 1 cm in size with a narrow viewing angle of 3 degrees is about as good as it gets.
The more impressive holograms in recent years, like a memorable one of Tupac Shakur, were actually two-dimensional projections, while others require special equipment like augmented reality goggles such as Microsoft's HoloLens. In essence, these are really just optical illusions.
To move towards bringing actual holographic projections up to snuff, researchers at the Korea Advanced Institute of Science and Technology (KAIST) used a deformable mirror, which is one type of wavefront modulator, and a pair of successive holographic diffusers to scatter light in many directions. This boosts the viewing angle and size of the image, but all that scattered light also creates a type of interference called volume speckle fields, which aren't compatible with displaying 3D images.
The team was able to employ an optical modulation technique to control the fields and the result was a 3D holographic image measuring 2 cm in width, length and height and a much improved viewing angle of 35 degrees. The researchers claim this was about 2,600 times stronger than the original image definition created without the use of a diffuser.
"Scattering light has previously been believed to interfere with the recognition of objects, but we have demonstrated that current 3D displays can be improved significantly with an increased viewing angle and image size by properly controlling the scattered light," said KAIST professor YongKeun Park.
The researchers see this advance as a significant start towards creating practical holographic displays that could be put to use by doctors for imaging, engineers for design and improving other related technologies like virtual reality.
The research was published in the journal Nature Photonics.
Source: KAIST via EurekAlert