Laser-Powered Tractor Beam Could Move Tiny Particles - 6:43 PM -
Categories: Physics Another piece of Star Trek technology has
become a reality. Captain Kirk would instantly recognize new
blueprints developed by a team of Chinese scientists as plans
for a tractor beam. The proposed device hasn’t yet been built.
But a similar one conceived by an American physicist was tested
last year. Each device would fulfill the science fiction dream
of reeling in objects using light — though neither could move
anything bigger than a bacterium, much less a starship. The
Chinese plan, reported online Feb. 24 at arXiv.org, would use a
laser to produce what is called a Bessel beam. This beam,
unusual because it remains focused over large distances, could
induce electric and magnetic fields in an object in its path.
The spray of light scattered forward by these fields could push
the object backward, against the movement of the beam itself.
“This analysis established that light can indeed pull a
particle…. Under appropriate cond