It's pulling us in! Researchers make tractor beams a reality
By Darren Quick
September 9, 2010
In a move that is sure to warm the hearts of those in the upper echelon of the Galactic Empire, researchers have taken tractor beams from the realm of science fiction to the realm of science fact. The researchers from the Australian National University (ANU) have developed a laser beam that can move very small particles up to distances of a meter and a half (4.9 feet) using only the power of light. Unfortunately this means it won’t be able to reel in anything the size of the Millennium Falcon, and the fact it won’t work in the vacuum of space probably won’t help matters either, but it’s a remarkable breakthrough nonetheless.
Professor Andrei Rode’s team from the Laser Physics Centre at ANU used a hollow laser beam to trap light-absorbing glass particles in a ‘dark core’. The particles are then moved up and down the beam of light, which acts like an optical ‘pipeline’.
“When the small particles are trapped in this dark core very interesting things start to happen,” said Dr Rode. “As gravity, air currents and random motions of air molecules around the particle push it out of centre, one side becomes illuminated by the laser whilst the other lies in darkness. This creates a tiny thrust, known as a photophoretic force that effectively pushes the particle back into the darkened core. In addition to the trapping effect, a portion of the energy from the beam and the resulting force pushes the particle along the hollow laser pipeline.”
Professor Rode said there are a number of practical applications for this technology, including directing and clustering nano-particles in air, the micro-manipulation of objects, sampling of atmospheric aerosols, and low contamination, non-touch handling of sampling materials.
“On top of this, the laser beam could be used for the transport of dangerous substances and microbes, in small amounts,” he said.