Real-Life Tractor Beam

Physicists at New York University have demonstrated a micro-tractor beam capable of pushing and pulling molecules...

Science Fiction movies are full of technological ideas that inspire future developments. But a real life tractor beam seems pretty far fetched...until now. For those who aren't science fiction fans, a tractor beam is a device that uses energy to push or pull objects toward itself.

New York University physicists are working on assembling a real life tractor beam. To create the tractor beam, David B. Ruffner and David G. Grier, overlapped two Bessel beams using a lens. (Bessel beams are a type of laser that directs light in concentric circles rather than as a single point, and are capable of reconstructing themselves after partial obstruction.) When directed onto an object the combined beams were able to push and pull tiny objects back toward the beam's source.

"These optical conveyors have periodic intensity variations along their axes that act as highly effective optical traps for micrometer-scale objects." Grier explains, "One way to describe this is that the combined beam is sort of like a wave (of intensity) on top of a wave (of light). The light wave travels downstream, just as light does. The intensity wave on top travels back toward the source and carries illuminated objects with it. A trapped particle is much like a surfer riding the intensity wave back up the light wave."

The duo's tractor beam is closer to the traditional science fiction concept of light-based transportation as it emits from a single source rather than relying on light from opposing points of origin to move the matter up and down stream. It is also reportedly more stable than other options: "Optical conveyors thus have the potential to out-perform optical tweezers, which cannot always achieve stable axial trapping," state Ruffner and Grier.

While the current design is only suited for moving microscopic particles, the team is already making suggestions to improve the mini tractor beam. Including improving speed of transportation by using a brighter conveyor and using higher order conveyors to transport oddly shaped objects. 

Upgrading the device to move large objects is impractical at present, since far more energy would be required. In fact, so much energy would be required that the object being moved would be destroyed. But the research does suggest that such a device might be feasible...enough evidence that last year NASA had funded a $100,000 study of tractor beams with that goal in mind.

So yea the possibility of creating real life full scale tractor beams is possible...but the possibility of finding hot alien chicks on a nearby planet is still pretty far fetched... 

Ruffner's and Grier's research was recently published in "Physical Review Letters".