Holograms have long been a staple of science fiction movies such as Star Trek or Star Wars -- but they're no longer the works of fiction. Researchers in Britain have engineered a display prototype that simultaneously produces visual, auditory and tactile content. This means that 3D representations -- such as a butterfly, a globe, or an emoji -- can be seen, heard, and touched without the need for an external device like a virtual reality headset.
This isn't the first holographic display. However, unlike previous renditions that are rather slow and short-lived, this version can produce tactile and auditory content, not just a 3-D image.
In order to allow users to interact with the hologram with their hands, the prototype employed acoustic tweezers that can move and manipulate tiny objects. In this case, particles that can be illuminated in red, green and blue (RGB) light to control the color of the 3-D images just like on any regular display. Previously, acoustic tweezers were employed to successfully to levitate objects.
Essentially, the Multimodal Acoustic Trap Display (MATD) made by researchers at the University of Sussex uses a small array of tiny speakers to both trap particles and generate sounds, as well as generate tactile feedback. All of this -- seeing, hearing, and touching -- makes the hologram genuinely seem like a real object.
In one demonstration, the researchers generated a holographic countdown timer that the user can start and stop by simply tapping their fingers.
"Even if not audible to us, ultrasound is still a mechanical wave and it carries energy through the air. Our system directs and focuses this energy, which can then stimulate your skin to feel content," Ryuji Hirayama, lead author of the new study, told AFP.
"The feeling of the tactile sensation is like a gently spraying your hand with pressurized air."
Besides the obvious uses for entertainment, the researchers say that their prototype could find other useful uses from computing to biomedicine, allowing researchers to visualize complex systems in unprecedented detail.
The findings appeared in the journal Nature.