Sep 13 2010
Australian National University researchers have developed a new device, which can move tiny particles to a distance of 1.5 m using a light beam. This development could lead to new advancements in laser tweezers for biomedical research, sample taking, and for transporting dangerous microbes and substances.
Tractor beam
The device operates by producing a laser beam around the small glass particles. The air, which is surrounding the glass particles, gets heated up. However, the laser beam’s dark center remains cool. Once the particle drifts into the laser beam, the heated air molecules begin to bounce and hit the surface of the particle. This force is sufficient to nudge the particle back to the center.
In addition, a small amount of light enters the beam’s darker middle region and heats the air on one part of the particle. The light pushes the particle along the beam’s length. When an additional laser is positioned on the opposite side of the laser beam, both direction and speed of the particle can be controlled by varying the beam’s brightness.
A researcher associated with the project, Andrei Rhode stated that the new laser device could work in longer distances. With the type of laser and particles the researchers are using, particles can be moved as high as 10 m in air, Rhode said.