Scientists Use Graphene to Construct Tractor Beam

Physicists in China report that they have built a tractor beam capable of moving objects on the macroscale.

In the latest issue of Optics Express, the group reports that when using a 90mW laser, their tractor beam in a box can produce about a micronewton of pulling force. The setup is deceptively simple. The scientists vapor-coated a sliver of glass with reflective gold, and then stuck a flake of cross-linked graphene to the other side. Then, they pointed blue, cyan, and green lasers at the flake of graphene. Lo and behold, it moved toward the laser emitter.

The setup is built on established technology. Optical tweezers and solar sails also use light to move things around. However, optical tweezers usually confine themselves to objects the size of single molecules. Not so for this experiment, says the team.

“In previous studies, the light-pulling force was too small to pull a macroscopical object,” said research team member Lei Wang from China’s Qingdao University of Science and Technology. “With our new approach, the light pulling force has a much larger amplitude. In fact, it is more than three orders of magnitude larger than the light pressure used to drive a solar sail, which uses the momentum of photons to exert a small pushing force.”

Read More at Extreme Tech

Read the rest at Extreme Tech