Australian Physicists Build Reversible Tractor Beam

An anonymous reader writes: Physicists at Australian National University have developed a tiny tractor beam that improves in several ways upon previous attempts. First, it operates on scales which, while still tiny, are higher than in earlier experiments. The beam can move particles up to 200 microns in diameter, and it can do so over a distance of 20 cm. "Unlike previous techniques, which used photon momentum to impart motion, the ANU tractor beam relies on the energy of the laser heating up the particles and the air around them (abstract). The ANU team demonstrated the effect on gold-coated hollow glass particles. The particles are trapped in the dark center of the beam. Energy from the laser hits the particle and travels across its surface, where it is absorbed creating hotspots on the surface. Air particles colliding with the hotspots heat up and shoot away from the surface, which causes the particle to recoil, in the opposite direction. To manipulate the particle, the team move the position of the hotspot by carefully controlling the polarization of the laser beam."

Comments

Re:Still a long way to go ...

[sg_oneill]

Eh, the original Enterprise NX01 did pretty well for itself just using a good old fashion grappling hook. Plus slamming your foe with a grappling hook makes for bad-ass space fights.

Pusher beam, not reversible tractor beam

[BitZtream]

Lets learn to speak the language, shall we?

Tractor's pull. A tractor beam would pull. This pushes. It can't pull. This means its not a reversible tractor beam, which would mean it can pull and be reversed to push ... it can only push.

Its a pusher beam, and it only works in a fluid, on objects with tiny amounts of mass that can stand to be roasted into oblivion in order to move them less than distance of a reasonable sized dictionary.