I never thought I’d see the day in which holograms moved from the realm of science fiction into everyday reality, but here we are. Computer-generated holography has actually been around for decades, but it’s a technology whose use has been relegated to specialized fields such as optical microscopy and metrology. Thanks to 3D technology, however, we may soon be using holograms in everyday life, with no special equipment needed other than a smartphone.
A team of researchers led by RMIT University Distinguished Professor Min Gu has designed a nano-hologram that can be seen without 3D goggles and is 1,000 times thinner than a human hair. According to RMIT, it’s the thinnest hologram ever created.
“Conventional computer-generated holograms are too big for electronic devices but our ultrathin hologram overcomes those size barriers,” said Gu. “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. 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. From medical diagnostics to education, data storage, defence and cyber security, 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 an illusion of three-dimensional depth, but that requires that the holograms be at least the thickness of optical wavelengths. The RMIT team, working with researchers at the Beijing Institute of Technology, circumvented these limitations with a 25-nanometer-thick hologram based on a topological insulator material, a quantum material that holds a low refractive index in its surface layer but a high refractive index in the bulk.
The thin film created by the topological insulator acts as an intrinsic optical resonant cavity, which enhances the phase shifts for holographic imaging.
The research was documented in a paper entitled “Nanometric holograms based on a topological insulator material,” which you can access here.
“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. Zengji Yue, one of the authors of the paper. “This involves shrinking our nano-hologram’s pixel size, making it at least 10 times smaller. But beyond that, we are 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.”
It might not be long, then, before we’re walking around with 3D images floating above our watches and smartphones. The technology could also be used to create anti-counterfeit stamps for credit cards and currency.
“Compared with the fabrication methods of metasurface holograms, the DLW method does not require the complicated substrate treatment and the mask preparation process,” the researchers state. “Hence, the DLW fabricated nanometric holograms are more suitable for large-scale practical application.”
Authors of the research paper include Zengji Yue, Gaolei Xue, Juan Liu, Yongtian Wang and Min Gu. Discuss in the Hologram forum at 3DPB.com.
