New display tech paves the way for 'most realistic' holograms in regular eyeglasses

Researchers have invented a device that’s small enough to fit in a regular pair of glasses and could solve an age-old trade-off in holographic displays — leading to the most realistic holograms ever. 

Holograms are conventionally created using projecting devices called spatial light modulators (SLMs). Light is emitted through the device so that it changes the shape of the light wave at a specific distance, creating a visible surface.

But because SLMs are made from liquid crystal/silicon (LCoS) display technology, current hologram technology is suited to narrow fields of view like a flat screen or small viewing area (ie a small object). The viewer must be positioned inside a narrow viewing angle – anywhere outside it and the light diffracts too much, making the light invisible.

It's possible to widen the angle within which the image is clear, but fidelity is lost because current LCoS technology doesn't have the number of pixels available to maintain the image across a wider field. That means holograms tend to be either small and clear or large and diffuse, sometimes disappearing altogether if the viewer looks in another direction that's far enough away from the angle within which it’s visible.

Related: New invention transforms any smartphone or TV display into a holographic projector

Felix Heide, assistant professor of computer science at Princeton and the paper's senior author, explained how important the viewing angle is. “To get a similar experience using a monitor, you would need to sit right in front of a cinema screen," he said.

The new technology, detailed in a study published April 24 in Nature Communications, could lead to the creation of more detailed holograms no matter which direction the viewer is looking in or how fast they change direction. The apparatus required to project them too is so small and light that wearers don't need tools like bulky VR headsets.