St Andrew University in Scotland has successfully turned a laser into a tractor beam. Tractor beams are the tools of every Science Fiction author and something no spacecraft of the future has ever left home without.
NASA just last year was investigating three different technologies in its quest for different methods to deliver interplanetary items to a robotic rover or orbiting spacecraft, but alas it was not to be. One of the methods was the Bessel Beam which was decided not to have enough strength for moving say a car, aircraft, or a spacecraft, but they felt it had other applications in life.
The tractor beam that St. Andrew’s has developed at present has only been demonstrated on the microscopic level. It works relatively simply. A negative force that is produced through a mixture of certain properties of light, a Gaussian beam (following the profile derived in a Gaussian mathematical formula) is generated by a VERDI V5 laser. Once it is directed through a lens then passes through a suspension that has the electrical conductivity of less than one millionth of an ampere of a volt as well as two spheres and is set between two smear slides with no liquid. The beam is then reflected back by a mirror and the incoming beam and the reflecting beams interfere with one another producing a standing wave. The standing wave forces the spheres back toward the laser source.
Though to date it has only worked at the microscopic level, the research team at St. Andrews sees the possibilities in either biomedical photonics or other areas such as optical sorting.
Whether this will be further developed to pull a fuel depleted spacecraft to homebase or a Romulan bird of prey into a trap, it seems St. Andrews is helping us on gain some ground in making Science Fiction Science Reality.
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