Taking inspiration from movies like Star Wars that came out in the late 70s, countless science fiction movies have used the trope of mobile holograms capable of producing human speech ever since. With the latest advances in science (minus the fiction), this may actually soon become a reality.
According to a group of researchers from the University of Sussex and the Tokyo University of Science, however, a prototype they’ve created in their lab – detailed in a recent paper out in the journal Nature – allows them to create three-dimensional holograms which provide a genuine tactile experience.
Currently available holograms are quite good at reproducing images, but are also “slow, have limited persistence-of-vision capabilities and, most importantly, rely on operating principles that cannot produce tactile and auditive content as well”.
The prototype, called a Multimodal Acoustic Trap Display (MATD), is able to “simultaneously deliver visual, auditory and tactile content” through a process known as “acoustophoresis” whereby sound waves are used to manipulate physical objects (in this case – particles) to create an image inside a box decked out with tiny speakers.
“Our system traps a particle acoustically and illuminates it with red, green and blue light to control its colour as it quickly scans the display volume,” wrote the researchers in their paper. Since the system is based on sound waves, it can also produce audible sounds and, crucially, a degree of tactility.
“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,” explained co-author on the paper Nobuyuki Hirayama. “The feeling of the tactile sensation is like a [sic] gently spraying your hand with pressurised air.”
In addition to being exciting in its own right, the technique could open the door to non-contact, high-speed manipulation of matter, which might come in handy in a variety of areas, from computation to biomedicine.