A small amount of laser light leaks into the cool core of the tube, exerting a small amount of pressure on the particles. The result? The particles move along the beam.
By placing another laser at the other end of the tube and adjusting the brightness of both lasers, the particles can be controlled.
Although the team were limited by the size of the optical table in the lab (1.5 meters long), Andrei Rhode, one of the researchers involved in the study, thinks particles can be transported a distance of up to 10 meters.
But you may notice a problem with this technique if you wanted to install the laser-tractor beam on the USS Enterprise. This system needs to be operated in an atmosphere, not in a vacuum - the glass particles are kept in place by laser-heated air molecules after all.
Still, there are a huge variety of applications this burgeoning tractor beam has on Earth. For one, this could be used to transport dangerous microorganisms "hands free" in biomedical facilities; a step-up from the optical tweezers already in use. It could also be used in the construction of sensitive microscopic machines.
So, will Star Trek‘s tractor beam ever be possible? Unless gravitons are discovered, it would seem this technology is unlikely at best.
However, that's been said about another Star Trek favorite: the warp drive. Assuming the existence of dark energy, tiny extra-dimensions and a method to generate a shedload of energy, advanced propulsion expert Richard Obousy thinks zipping around the cosmos at warp speed could have potential.
It's apparent to me that a lot of people seem to want to prove why a technology is not possible, rather than think of ingenious ways to make something possible. It's my conviction that when someone says something is "impossible," what they really mean is "our current level of science cannot explain this, and I don't have the motivation to explore beyond its boundaries." –
Image credit: Australian National University