Scientists go sci-fi with laser-powered 'tractor beam'

Summary:Science fiction is once again becoming science fact. Like a starship's tractor beam, scientists have used specially patterned lasers to pull objects. A paper details the experiment.

A close up view of a Bessel beam. Image Credit: California Institute of Technology

The science of Star Trek is (theoretically) becoming a reality. The BBC is reporting that physicists have figured out how to draw objects closer with a laser powered “tractor beam.”

Researchers in Hong Kong and China have published a paper describing how objects can be pulled on a “wind of light” by deploying specialized lasers called Bessel beams.

Bessel beam lasers have precise patterns of light that form wave like ripples; a wave directed at the appropriate angle may ‘pull’ an object.

Outside of physics, they have been used to insert materials into living cells.

We show explicitly that the necessary condition to realize a negative (pulling) optical force is the simultaneous excitation of multipoles in the particle and if the projection of the total photon momentum along the propagation direction is small (as in some propagation invariant beams), attractive optical force is possible,” the paper states.

“This possibility adds "pulling" as an additional degree of freedom to optical micromanipulation.”

This is not the first time the feat has been attempted. Last year, physicists at the Australian National University devised a technique to move tiny glass particles nearly two meters across a laboratory.

However, the system would cease to operate in the vacuum of space: It requires superheated air to suspend objects.

Efforts to research a tractor beam type effect date back to the 1960’s. Fringe physics theories have involved directing “anti-gravitational force” towards or away from an object, gravity beams, and floating objects above electromagnetically levitated superconducting disks.

23rd century technology functions very differently. In Star Trek, a starship’s tractor beam utilizes so-called attenuated linear graviton beam to move around other sub-warp objects such as asteroids or enemy vessels.

Here’s some more analysis of Star Trek science:

This post was originally published on Smartplanet.com

Topics: Innovation

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