image: 'Half-twists of light.' Beams of light are streams of photons, and can form optical screws, in which the photons follow turning, twisting paths. There is a minimum twist for each photon. This twist can be halved by winding the light into Mobius strips, as depicted here. This material relates to a paper that appeared in the April 29, 2016, issue of Science Advances, published by AAAS. The paper, by K.E. Ballantine at Trinity College Dublin in Dublin, Ireland, and colleagues was titled, 'There are many ways to spin a photon: Half-quantization of a total optical angular momentum.' view more
Credit: Paul Eastham