Bending light beyond 10 degrees

New Scientist : Light normally travels in straight lines, but physicists have known for years that superimposing a pattern on a laser beam can make it bend. The pattern is designed to cause the beam’s individual light rays to interfere with each other in a way that makes the beam curve. Past experiments suggested that the maximum amount a beam could be bent was 10 degrees, but in theory one could be bent to 180 degrees . A group led by John Dudley at the University of Franche-Comté in Besançon, France, has now found a way to go beyond the 10-degree limit. The researchers have bent beams just a few micrometers across by up to 60 degrees using a spatial light modulator to superimpose the interference patterns ( Optics Letters , in press). The technique could be used to develop new micro instruments for surgery or for manipulating nanoparticles.