A long-distance optical tractor beam can move tiny particles - one fifth of a millimeter in diameter - a distance of up to 20 centimeters, which is almost 100 times further than previous experiments.

The hollow laser beam is bright around the edges and dark in its center and it can be used to attract or repel objects.

Get ready to control the weather or capture an X-Wing fighter in space - if it's really close, that is.

Dr. Vladlen Shvedov (L) and Dr. Cyril Hnatovsky adjust the hollow laser beam in their lab at the Australian National University. Credit: Stuart Hay, ANU

"Demonstration of a large scale laser beam like this is a kind of holy grail for laser physicists," said Professor Wieslaw Krolikowski, from the Research School of Physics and Engineering at The Australian National University.

"Because lasers retain their beam quality for such long distances, this could work over meters. Our lab just was not big enough to show it," said co-author Dr Vladlen Shvedov. 

Unlike previous techniques, which used photon momentum to impart motion, the new tractor beam relies on the energy of the laser heating up the particles and the air around them. The team demonstrated the effect on gold-coated hollow glass particles.

The particles are trapped in the dark center of the beam. Energy from the laser hits the particle and travels across its surface, where it is absorbed creating hot spots on the surface. Air particles colliding with the hot spots heat up and shoot away from the surface, which causes the particle to recoil, in the opposite direction.

To manipulate the particle, the team move the position of the hots pot by carefully controlling the polarization of the laser beam.

"We have devised a technique that can create unusual states of polarization in the doughnut shaped laser beam, such as star-shaped (axial) or ring polarized (azimuthal)," Hnatovsky said. "We can move smoothly from one polarization to another and thereby stop the particle or reverse its direction at will."