A team of researchers at the University of St Andrews School of Medicine, led by Dr. Tomas Cezak, have recently constructed a microscopic tractor beam out of a laser.
For those of you unfamiliar with science fiction genre conventions such as tractor beams here’s a quick explanation. A tractor beam is a fictional device seen in many classic works of science fiction, a beam of energy that is capable of capturing a spaceship and pulling it towards the source.
In science fact, however, tractor beams work a little differently. Dr Cezak’s team’s work is based on a well-known principle, discovered by 17th century astronomer Johannes Kepler. Kepler noted that a comet’s tail always pointed away from the sun, no matter what direction it might be moving. From this observation, he correctly hypothesized that the tails of the comets where being shaped by the pressure of oncoming sunlight.
The remarkable trick the team at St Andrews has pulled off is another old sci-fi staple: they reversed the polarity. By reflecting a carefully tuned laser through a suspension of dielectric spheres, the team created a standing wave that pushed the spheres back toward the oncoming laser beam.
While amazing, the technology won’t break atmosphere anytime soon – the team have applications a bit closer to home in mind. First and foremost is the creation of a cheap and efficient device to sort cells and organelles for bio-medical research.
Images and Video Courtesy of University of St. Andrews & New Scientist