Researchers from the Australian National University have built a working tractor beam of sorts, ensuring that those wily rebels won't get far, as long as their spaceship is the size of tiny glass particles.
We might not be towing starships anytime soon, but if you need to move small particles about a meter and a half using only the power of laser light, then this device is the one you've been waiting for.
It's actually rather simple. Particles of glass are suspended inside a hollow laser beam. While the outside of the beam grows hot, the center stays cool, due to a process scientists absolutely do not call the McDLT effect. If the particle starts to stray towards the sides, agitated heated air molecules push it back towards the center of the beam. By placing a laser at either end, scientists can manipulate the intensity coming from each side. If more heat comes from one end, it'll push the molecule towards the other.
Actually it sounds a little bit like the Excursion Tunnels showing up in Valve's Portal 2, only much smaller.
At the moment the distance the device can transport molecules is limited, but Andrei Rhodes, a researcher with the project, believes they can take it even further.
"With the particles and the laser we use, I would guess up to 10 meters in air should not be a problem. The max distance we had was 1.5 meters, which was limited by the size of the optical table in the lab," Rhode said.
Someone get those guys a bigger table.
As for practical applications, since the lasers require heated gas to function, spaceship towing is out of the question. It could be used to transport hazardous materials or move glass particles around, if you're into that sort of thing.
And who knows? Maybe one day Excursion Tunnels will be a reality, and all of us will be killed by a sentient computer. Hooray!
Tractor beams come to life [Physorg.com]