Here’s one to add to your Christmas wish list: a laser beam that has the power to move objects from one location to another. What may seem like science fiction (Star Trek fans, eat your hearts out!) is now actually the stuff of science fact! A group of researchers have found out just how to make a real life tractor beam that is able to move objects, albeit microscopic ones, or keep them stationary. It may be less impressive than the tractor beams featured in Star Trek but it is certainly a step in the right direction!
Led by the University of St. Andrews, the new research follows on from ideas of Johannes Kepler, a German Astronomer in 1619. Kepler’s observations of comets led to the conclusion that microscopic objects follow the direction of light photons (‘packets’ of light) when hit by a beam of light. This new piece of research has focused on a technique to reverse this force, effectively allowing small objects to be ‘pulled’ towards a beam of light.
Although the technique is quite recent, its potential applications are huge. The beam is already gaining popularity amongst all manners of disciplines. From a medical perspective, the beams could be used to separate mixtures of substances or chemicals by focusing on particular aspects of the mixture. For example, isolating white blood cells from a typical sample of blood. Aside from medicine, the tractor beam also has the potential to be used by NASA as a way of collecting atmospheric or dust samples from space.
However, there are obstacles that will need to be overcome before we can recreate a Star Trek-like beam capable of trapping space ships, which we’ve seen on sci-fi shows. Mainly because scaling up the beam size will create an immense transfer of energy that will cause huge overheating issues; your tractor beam suddenly becomes a superheating death ray. Perhaps not the intended use…
But regardless, for now at least we know that such a beam exists. It may not meet the specifications of the U.S.S. Starship Enterprise of the Star Trek series, but for now, it is definitely enough of an achievement to impress.
Brzobohatý, V. Karásek, et al., Nature Photonics: 7, 254 (2013)