Researchers Create Real Tractor Beams

Gadgetank writes "Researchers out of the Australian National University have created a device, working in conjunction with other necessary devices, that can literally move small particles with light. And only light. The way it works is by shining a hollow laser beam around some tiny glass particles. The researchers heat the air around the particles, and therefore cause the dark center of the beam to remain cool."

Re:not a real tractor beam

[wierd_w]

Actually, Wasn't there an article about a month ago here on slashdot about the "Maximum effective energy" a laser can reach, before the photon flux itself breaks down into antiparticle pairs? A similar effect could be attained using a modification of the optical tweaser approach used here, that WOULD be effective in space. (It would, however, also tend to vaporize whatever you shined it at... but Meh.) Namely, you add another "layer" in your optical tweasers, at a very very high photon flux. This will create antiparticle pairs in one part of the beam path (middle layer), the less energetic optical confinement stream (outer layer), and then the "cavity" in the center. Due to the self-scattering caused by the antiparticle pair production, this approach would have very limited range, but would at least partially solve the "no atmosphere" problem. (I wouldnt expect to move a huge asteroid this way; the vented gasses caused by hitting it with that much photon flux would provide vastly more propulsive force than that of the optical tweaser effect... but if you absolutely MUST move a particle in what is otherwise a vacuum, this kind of thing might work. Just keep it small enough to fit in the cavity, and OUT of the high flux layer. I just can't think of any reason why you would want to do this though. )

Re:not a real tractor beam

[Gary Perkins]

I think it's more likely cultural difference. American English seems to have minor differences in the meanings of words.

I know as far as a driveway, most everyone here doesn't really have one. It's more like parking spaces. But we call them driveway's anyways.

I'm surprised I started this whole discussion. I was actually just alluding to some jokes by one or two popular American comedians. It's been repeated often enough that I couldn't begin to remember who, but the point of the joke is simply that English really is somewhat of a backwords language compared to most of the world.