Watch this space for holographic movies
You might one day be able to immerse yourself in 3D holographic movies thanks to new technology reported today.
US researchers unveil in the journal Nature details of 3D holograms that can be updated almost in real time.
Other beneficiaries of the technology include military commanders, who could gain a 3D picture of a battlefield, and surgeons performing complex micro-surgery.
Professor Nasser Peyghambarian of the University of Arizona and colleagues report how they recorded, displayed and updated images on a palm-sized screen measuring 10 centimetres by 10 centimetres.
Holograms are created by shining a laser on an object, whose image falls onto a photosensitive screen.
At the same time, a second laser beam falls on the screen, creating an interference pattern, in essence, the condensed contours of the object, which are embedded in the film.
It takes a third laser, called the reading beam, to be directed onto the screen for the interference pattern to be resurrected.
To a person in front of the screen, this creates a 3D image that appears in mid-air behind the screen.
These holograms are widely used in advertising, art and entertainment but the drawback is that their displays are static.
The new technology, though, can store the image, erase it and update it, say the inventors.
Although still at a prototype stage, it means that one day a 3D motion picture is a clear possibility, they believe.
The secret lies in films called photorefractive polymers that contain molecules of dye that respond to light and rotate and line up in response to an applied electrical field.
On their small display, Peyghambarian's team were able to update the image in about 3 minutes and hold it there for up to 3 hours.
But anyone hoping for a zappy Star Wars-style hologram that can be viewed from any point in the room would be disappointed.
The parallax, or 3D effect, still can only be seen within a given angle by a person in front of the screen. Move too far to the right or left or up or down, and the effect is lost.
Professor Joseph Perry of the Georgia Institute of Technology in Atlanta, in a commentary published by Nature, says the innovation is extraordinarily promising, not least because the polymers were potentially cheap and easy to produce.
It is only a matter of time before higher-powered lasers and more sensitive photorefractive polymers ushered in larger and faster 3D displays, he says.
"The technology still has some way to go to maturity but ultimately it's not just the cineastes who could benefit," he says.
"Displays that provide realistic 3D images with a wide angular viewing range might also be used in military or medical contexts, such as the simulation of field situations or the guidance of keyhole surgery."
But he notes holographic displays could face fierce competition from flat-panel 3D screens and other rivals.