The tractor beam, a beloved staple of science fiction, has been inching closer and closer to reality. We’ve got physicists building optical beams that can pull micro-scale balls through water. NASA and Arx Pax (of “hoverboard” fame) are building a magnetic tractor beam that can control satellites. The latest incarnation of this Star Trek-inspired technology? A sonic hologram.
Writing in Nature Communications this week, a team of physicists reports a new method to levitate and manipulate small objects, using what they call “acoustic holograms.” Basically, the researchers built an array of miniature loudspeakers that create high-pitched and high-intensity sound waves. By enveloping a small object in sound, the team essentially creates a “force field” that can be used to hold said object in place, rotate or manipulate it any which way.
These researchers have designed several different versions of a device with tractor beam-like properties, including an acoustic field that resembles a pair of fingers, a sonic vortex that sucks object in, and an acoustic “cage” that surrounds an object and holds it in place from all directions. (That last one sounds uncomfortably similar to a popular Sith interrogation technique.)
While presently, the researchers’ acoustic fields have only been used to manipulate teeny tiny balls, in the future, this technology might be able to transport and assemble small, delicate structures without touching them, perhaps even deliver drug capsules or perform microsurgery within living tissues. As for capturing Romulan Birds-of-Prey that stray past the neutral zone….well, that might still be a few centuries off.