Phys.org June 10, 2019
An international team of researchers (Spain, Austria, USA- University of Colorado) has designed a beam of light with a polarization state that forms three-lobed trefoils at each point by combining light of different frequencies (w and 2w), and making the trefoils connect to each other in a way such that the light beam, as a whole, has the shape of a knot. They found new conservation laws for non-linear optics which hold even in extreme situations where tens or hundreds of photons get combined to form single high-frequency photons and a new optical singularity, robust against perturbations, caused by the different orientation of the polarization trefoils at different points around a circularly-polarized center. The findings could be used to store valuable information, opening the possibility of using these new topologies of light for future communication applications, among others…read more. TECHNICAL ARTICLE 1 , 2