Tractor Beams Now A Reality On A Very Small Scale
With the recent funding of the 100-Year Starship initiative, it seems more and more likely that Star Trek might be a reality in the future. On top of possibly one day building the U.S.S Enterprise, researchers have proven that a tractor beam is possible on a very small scale.
In a study published in November 2011, researchers at the A*STAR Data Storage Institute theoretically proved that they can use a laser to pull particles towards them.
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Albert Einstein and Max Planck realized more than a hundred years ago that when light strikes a particle, the momentum of the light beam can actually push objects away.
Haifeng Wang and his co-workers used lasers with a particular distribution of intensity across their spectrum known as Bessel beam.
In this case, Wang says that if the particle is small enough, then the beams will actually bend around the particle rather than bounce off of it. This is turn creates a suction effect, where the particle will then move towards the source of the laser rather than away from it.
According to Wang, "These beams are not very likely to pull a human or a car, as this would require a huge laser intensity that may damage the object. However, they could manipulate biological cells because the force needed for these doesn't have to be large."
One medical application would be to investigate whether cells are healthy or have been infected. For instance, a blood cell infected with malaria is more rigid than a healthy one. By using a laser tractor beam, one could measure how the cell reacts and its tensile strength.
A previous study published in 2011 demonstrated that one can use two different beams of light to manipulate particles to a certain degree. While a similar concept, it is not the same as the traditional tractor beam that science-fiction has instilled in our imaginations.