Aussie researchers create working tractor beam
“Hollow” laser beam moves glass particles over large distance.
Australian National University (ANU) professor Andrei Rode and researchers at ANU’s Laser Physics Centre have developed a laser beam that can move small transparent particles more than a meter and a half.
The team’s laser works by trapping transparent particles in a “dark core.”, a hollow channel at the laser’s center. As gravity and air currents push the particles toward the channel’s edges, one side of the particle reflects and refracts the light from the laser. In essence, the light creates thrust, or photophoretic force, that pushes the particle back to the center of the beam. Through a combination of direct and indirect photophoresis particles are moved down laser beam, which acts like an optical ‘pipeline’.
Although it won’t work in space, Rode says the breakthrough has applications including directing and clustering nano-particles in air, micro-manipulation of objects, sampling of atmospheric aerosols and low contamination, non-touch handling of sampling materials.