Tony Stark, aka Ironman, constantly seen manipulating 3D holographic images and floating displays projected in mid-air from his phone or tablet. Unfortunately, the rest of us are not as fortunate because the current computer-generated holograms are too bulky to be integrated into our personal devices. However, if a team of researchers from Australia's RMIT University and the Beijing Institute of Technology (BIT) is right, we may all soon be able to mimic Ironman, at least, when it comes to playing with 3D holograms.
A hologram is made using lasers because all the light waves are the same size and hence bend the same way. This means that unlike white light that splits into different colors when shined through a prism, a laser beam will emerge intact.
To create a hologram, a single laser beam is divided into two identical beams with the help of a special lens. One, dubbed the "reference beam," is shone directly onto a regular photo film, while the second is reflected off of the object intended to be transformed into a hologram. When the two laser beams meet, they create what is called an interference pattern. It is this pattern that is recorded on to the film to create the 3D illusion. However, current hologram technology is somewhat limiting, given that the material on which the light is recorded, has to have the same thickness as the light’s wavelength. As a result, it is too thick to incorporate into personal devices.
To bypass this hurdle, the scientists, led by RMIT University’s Min Gu, took advantage of the unique qualities of a topological insulator, a quantum material that has a low refractive index on its surface, and a substantially higher refractive index in the middle. This allows light to travel quickly through the surface and slow down as it penetrates the center, creating what is known as an optical resonant cavity. This causes the light in the lower layer to keep reflecting off the surfaces, generating multiple phases, which interact to form a hologram.
The researchers, who published their study in Nature Communications on May 19, 2017, assert that this has enabled them to create a hologram that measures a mere 60nm, or 1000 times thinner than a single strand of human hair. The easy to create projection can be observed from different angles without special goggles.
Dr. Zengyi Yue, the co-author of the study, says, "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. This involves shrinking our nano-hologram's pixel size, making it at least 10 times smaller.”
The team envisions that once ready, 3D holograms could be used for a wide variety of applications, including medical diagnostics, education, defense, and cyber security. The innovation has the potential to quite literally change the way we look at technology — forget FaceTime or video calling; we could soon be saying hello with a hologram!