New research twists beams of light

University of Glasgow scientists have helped to create silicon optical chips to generate twisted beams of light which could be used to manipulate tiny particles or increase the capacity of optical technology. A recent paper published in the journal Science outlines how an international research team involving the Universities of Glasgow and Bristol, along with colleagues at the Universities of Sun Yat-Sen and Fudan in China, have demonstrated integrated arrays of 'optical vortex beams' on a silicon chip. Michael Strain, research associate in Electronic and Nanoscale Engineering at the University, said: "The energy of the light in an optical vortex beam travels in a spiral, creating a hollow conical beam that looks much like a mini-vortex. When light in such beams interacts with matter it asserts a rotational force, making it useful as an 'optical spanner' or 'optical tweezers', which can rotate, as well as trap microscopic particles, droplets or single cells. "In addition, the different amounts of twist generated in the beam can be used to carry information, and so the capacity of a single channel can be greatly enhanced by transmitting signals with different values of twist at the same time." Marc Sorel, Senior Lecturer in Electronic and Nanoscale Engineering said: "A key issue for many applications is not just the ability to create beams with optical angular momentum but also the ability to integrate such optical vortex emitters into photonic circuits. "Previously, bulky laboratory equipment and sensitive optical alignment tools were required to produce optical vortex beams.