Published on May 28th, 2012 | by James Johnson0
Tractor Beam Becomes A Reality, Not Quite Star Trek Capable Yet
The idea of light pulling objects across a surface might sound like science fiction but those “tractor beams” are now a reality thanks to Haifeng Wang at the A*STAR Data Storage Institute. Wang and his team last week demonstrated the new tractor beam technology, albeit on a small scale.
According to Wang:
“Our work demonstrates a tractor beam based only on a single laser to pull or push an object of interest toward the light source.”
Albert Einstein and Max Planck more than one hundred years ago spoke about how light carries momentum that pushes objects away, it was using their principles and the realization that the intensity of a lser beam can push objects sideways that led researchers to their recent success.
While pushing an object away has been demonstrated it was until 2011 that researchers theoretically demonstrated a mechanism that could push and pull objects using two opposing light beams, although that idea is slightly different than a tractor beam because a light would have to help push the object instead of simply grabbing it and pulling.
According to Science Daily:
“Wang and co-workers have now studied the properties of lasers with a particular type of distribution of light intensity across the beam, or so-called Bessel beams. Usually, if a laser beam hits a small particle in its path, the light is scattered backwards, which in turn pushes the particle forward. What Wang and co-workers have now shown theoretically for Bessel beams is that for particles that are sufficiently small, the light scatters off the particle in a forward direction, meaning that the particle itself is pulled backwards towards the observer. In other words, the behaviour of the particle is the direct opposite of the usual scenario. The size of the tractor beam force depends on parameters such as the electrical and magnetic properties of the particles.”
Because higher intensity is needed for larger objects the current tractor beam technology would not be good for towing large objects which the high intensity laser beam would likely damage.