​Australian-Chinese research team claims world's thinnest hologram

A team comprised of researchers from Melbourne's RMIT University and the Beijing Institute of Technology (BIT) has announced the creation of the world's thinnest hologram, touting the invention as paving the way towards the integration of 3D holography into everyday electronics such as smartphones, computers, and televisions.

According to the team led by RMIT distinguished professor Min Gu, the challenge for scientists attempting to turn interactive 3D holograms into reality has been developing holograms that are thin enough to work with modern electronics.

"Conventional computer-generated holograms are too big for electronic devices but our ultrathin hologram overcomes those size barriers," Gu said. "Integrating holography into everyday electronics would make screen size irrelevant; a pop-up 3D hologram can display a wealth of data that doesn't neatly fit on a phone or watch."

The nano-hologram is apparently simple to make, can be seen without 3D goggles, and is 1,000 times thinner than a human hair.

"Our nano-hologram is also fabricated using a simple and fast direct laser writing system, which makes our design suitable for large-scale uses and mass manufacture," Gu explained.

"From medical diagnostics to education, data storage, defence, and cybersecurity, 3D holography has the potential to transform a range of industries and this research brings that revolution one critical step closer."

Conventional holograms modulate the phase of light to give the illusion of three-dimensional depth. But to generate enough phase shifts, those holograms need to be at the thickness of optical wavelengths, RMIT explained.

The Australian-Chinese research team said it has broken this thickness limit with a 25 nanometre hologram based on a topological insulator material, which it said is a novel quantum material that holds the low refractive index in the surface layer but the ultrahigh refractive index in the bulk.

But the team said the topological insulator thin film acts as an built-in optical resonant cavity, which can enhance the phase shifts for holographic imaging.

"The next stage for this research will be developing a rigid thin film that could be laid onto an LCD screen to enable 3D holographic display," said Dr Zengyi Yue, who co-authored the paper with BIT's Gaolei Xue.

"This involves shrinking our nano-hologram's pixel size, making it at least 10 times smaller.

Yue said the team is looking to create flexible and elastic thin films that could be used on a whole range of surfaces, opening up the horizons of holographic applications and a science-fiction world where holograms are part of everyday norms.

In January, a team of physicists from the Australian National University (ANU) announced the invention of a tiny device using infrared that creates the highest-quality holographic images ever achieved.

Lead researcher and PhD student at the ANU Research School of Physics and Engineering Lei Wang touted the complex holographic image advancement as opening the door to imaging technologies such as those seen in science fiction movies.

"While research in holography plays an important role in the development of futuristic displays and augmented reality devices, today we are working on many other applications such as ultra-thin and light-weight optical devices for cameras and satellites," Wang said at the time, noting that the device could replace bulky components to miniaturise cameras and save costs in astronomical missions by reducing the size and weight of optical systems on spacecraft.

According to ANU, holograms perform the most complex manipulations of light and enable the storing and reproduction of all information carried by light in 3D; standard photographs and computer monitors, however, capture and display only a portion of 2D information.