Scientists 'Tie Light in Knots'

A team of physicists say they’ve managed to “tie light in knots” using holograms and abstract mathematics. The breakthrough could have a host of practical applications, including more precise lasers and traffic speed guns. It’s also the first physical application of “knot theory,” a branch of mathematics inspired by the winding of shoelaces, which was previously believed to be totally abstract.

“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,’” explained one researcher. These optical vortices are often invisible to the naked eye, but his team was able to direct them using sophisticated holograms.
(More mathematics stories.)