The "tractor beams" described in science fiction are one step closer to becoming a reality, but the benefits could first be realized in medical laboratories before space.
Scientists from the Czech Republic and United Kingdom collaborated for several years to build an experimental tractor beam that was used to manipulate and sort microparticles (objects the size of tree pollen). The results of the experiments were published in the journal Nature Photonics on Jan 20 without any competing interests.
The scientists concluded that their approach was relatively simple enough to encourage broad adoption and that "ongoing investigations will broaden the understanding of the light-matter interaction through studies combining more interacting micro-objects with various properties," the study says.
Dr Tomas Cizmar, research fellow in the School of Medicine at the University of St Andrews, told the BBC News that tractor beams had practical applications such as selectively acting on a specific particle in a mixture, for example separating white blood cells from a blood sample. Snatching objects in space (like a space ship on a collision course, emerging from a temporal anomaly) would produce too much heat, he noted.
This is not the first attempt at building tractor beams. NASA announced its research project in 2011, and that same year, researchers in Hong Kong and China 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.
Tractor beam research dates 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 science, 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.
(image credit: memory-alpha)
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