Tractor beam closer to reality...

Tractor beam closer to reality...

(Phys.org)—David Ruffner and David Grier of New York University have developed a technique for using Bessel beams to draw a particle toward a source. In their paper published in Physical Review Letters they describe how they used their technique to pull 30 micrometer sized silica spheres suspended in water, towards a laser source.

A device that uses energy to pull an object towards a source is known as a "tractor beam" after the fictional technology of Star Trek fame. To date no such device exists, but this new work by Ruffner and Grier shows that it might be possible. Their work is based on a form of laser known as a Bessel beam.

A Bessel beam, named after its creator Friedrich Bessel, is a type of laser that directs light in concentric circles around a single dot rather than as a single beam. Unlike general laser beams, the light from a Bessel beam, at the dot, is not diffracted and because the dot is formed by light from the circles, it can reform if it encounters an object in its path. It's this property that allows for pulling a particle, the team found.

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