Tractor Beam
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Tractor beams are suddenly a lot more plausible
Tractor beams now have a better shot at crossing from science fiction trope to reality, thanks to scientists at The Australian National University (ANU). They managed to push and pull a 0.2mm sized particle nearly 20cm using a "hollow" laser beam. That's a hundred-fold improvement over recent efforts at light propulsion, which have only moved microscopic particles short distances. The ANU team placed gold-coated glass spheres in the light-free center of the beams, creating hotspots on the surface that propelled the spheres via air reactions. The hotspot's location was changed by adjusting the polarization, giving scientists full control over the sphere's motion. Sure, it's not exactly the Death Star, but the scientists think it'll work over long distances -- meaning it could one day be used to, say, control pollution or move dangerous particles in the lab.
Negative radiation pressure in light could make some tractor beams real, we're already sucked in
Developing a real, working tractor beam has regularly been an exercise in frustration: it often relies on brute force attempts to induce a magnetic link or an air pressure gap, either of which falls a bit short of science fiction-level elegance. The Technion-Israel Institute of Technology's Mordechai Segev has a theory that would use the subtler (though not entirely movie-like) concept of negative radiation pressure in light to move objects. By using materials that have a negative refraction index, where the light photons and their overall wave shape move in opposite directions, Segev wants to create a sweet spot where negative radiation pressure exists and an object caught in the middle can be pushed around. His early approach would use extremely thin crystals stacked in layers to manipulate the refraction. As it's theorized, the technology won't be pulling in the Millennium Falcon anytime soon -- the millimeters-wide layer intervals dictate the size of what can be pulled. Nonetheless, even the surgery-level tractor beams that Segev hopes will ultimately stem from upcoming tests would bring us much closer to the future that we've always wanted.
NASA developing tractor beams, no plans for Death Star... yet (video)
Fully functional LightSabre aside, a tractor beam has to be high on most geek wish-lists; lucky for you NASA has started working on one. Before you drop your sandwich (or whatever that object in your left hand is), this won't be for sucking up star cruisers, but the more modest task of sample and space dust collection. The basic concept has already been proven, but now NASA's Office of the Chief Technologist has given boffins $100,000 to make the dream a reality. Three potential methods are already on the table, which in lay-terms resemble laser tweezers, a light vortex and a conceptual rippling beam. Once developed, it could signal the end of traditional mechanical sample collecting -- and just plain luck -- consigning robotic arms to the history books. Check the video after the break for science-tastic mock up of how it might work.
Australian researchers trap tiny particles in tiny tractor beam
Lasers. Is there anything they can't do? The latest addition to the 50-year-old technology's bag of tricks comes courtesy of a team of researchers from the Australian National University, who've managed to create a laser beam that effectively functions as a tiny tractor beam. The key, it seems, is that the laser beam is hollow, which allows tiny particles to be trapped in what the researchers describe as a "dark core," which in turn causes the particles to be pushed along the beam by an effect known as the "photophoretic force." As you might expect, that only works on very tiny particles, but the researchers are able to move them as far as one and a half meters, and they say that the technology could have a number of practical applications, including directing and clustering nano-particles in the air, and even transporting dangerous substances and microbes -- in small amounts, of course. [Thanks, Lester]
