A scene from the film Avatar

New Delhi, Nov. 5: Scientists have announced an advance in optics and materials that may allow them to create true three-dimensional, moving, lifelike projections of people and objects — a feat not achieved so far.

While 3D display has become popular in films — including James Cameron’s 2009 epic Avatar — television and videoconferences, optics experts say all existing technologies provide only limited 3D perspectives.

Now, a university-industry research team in the US has for the first time demonstrated 3D telepresence through holography — a technology that uses lasers and special optical material to generate 3D images and transmit them to another location. The 16-member team has described its research work in the current issue of the journal Nature .

“This brings us a step closer to the ultimate goal of realistic holographic telepresence with high-resolution, full-colour, human-size 3D images that can be sent (as video) from one part of the world to another,” said Nasser Peyghambarian, chair of photonics and lasers at the University of Arizona, and a senior member of the team.

“Our 3D system shows different viewpoints of the object — when viewers move around, they can experience different aspects of a scene and literally look around corners,” the lead author Pierre-Alexandre Blanche said.

“The 3D information can be gathered by instrumentation and sent via the Internet,” Blanche told The Telegraph.

The research team had earlier developed a polymer-based display system that could refresh images only once every four minutes.

In the new work, Peyghambarian and his colleagues used a novel photo-refractive material, which refreshes images every two seconds — and is thus capable of supporting near real-time video images.

Existing 3D movies and 3D television and videoconferences use techniques called polarisation stereoscopy and digital image fusion but only create an impression of 3D by providing two slightly different perspectives.

“Only holography gives us true 3D images,” said Joby Joseph, an associate professor of physics at IIT Delhi who specialises in holography but is not associated with the work.

“In all existing 3D representations, when you move your head to the left or to the right, the perspective of the image does not change. If there’s a tennis ball behind a football, the existing 3D techniques don’t allow you to tilt your head and see the tennis ball behind the football. Holography will allow this,” Joseph told The Telegraph.

The US team has predicted that the technology may find applications across a range of fields — from telemedicine to entertainment. Surgeons could use the technology to observe 3D images of patients in real time and participate in the surgery from a distance.

But Joseph cautioned that the technology that the US researchers have shown appears to be “complex and expensive”. It demands a nanosecond pulsed laser, a high-precision scanner and a high voltage potential of 7 kilovolts across the material, he said. “It may be sophisticated and costly — so we’ll need to wait and watch how fast it heads towards applications.”

The technique uses a screen made of a novel photo-refractive material that can refresh holograms every two seconds. An array of cameras are used to produce multiple views of an object and the image information is encoded through laser beams and stored. For viewing, the patterns are reproduced to create a 3D image.