Physicists have tied “light in knots,” a breakthrough which they claim paves the way for a new level of precision in laser technology, with applications ranging from traffic speed guns to height measurement.
A British team has achieved the remarkable feat in which the light was controlled using holograms specially designed with “knot theory” — a branch of abstract mathematics inspired by twists in shoelaces and rope.
Dr. Mark Dennis of the University of Bristol, who led the team, was quoted by The Daily Telegraph as saying: “In a light beam, the flow of light through space is similar to water flowing in a river. Although it often flows in a straight line —— out of a torch, laser pointer, etc., —— light can also flow in whirls and eddies, forming lines in space called ‘optical vortices’.
“Along these lines, or optical vortices, the intensity of the light is zero (black). The light all around us is filled with these dark lines, even though we can’t see them.”
The team was able to create knots in optical vortices, using the sophisticated holograms to direct the flow of light, said Dr. Dennis.
Team member Prof .Miles Padgett of Glasgow University said: “The sophisticated hologram design required for the experimental demonstration of the knotted light shows advanced optical control, which undoubtedly can be used in future laser devices.”
Added Dr. Dennis: “The study of knotted vortices was initiated by Lord Kelvin back in 1867 in his quest for an explanation of atoms. This work opens a new chapter in that history.”
The findings have been published in the latest issue of the Nature Physics journal.