Denisenko, VladimirShvedov, VladlenDesyatnikov, Anton SNeshev, DragomirVolyar, AlexanderSoskin, Marat SKrolikowski, WieslawKivshar, Yuri2010-07-152010-12-202010-07-152010-12-20Optics Express 17.26 (2009): 23374-233791094-4087http://hdl.handle.net/10440/1037http://digitalcollections.anu.edu.au/handle/10440/1037We introduce a simple, single beam method for determination of the topological charge of polychromatic optical vortices. It is based on astigmatic transformation of singular optical beams, where the intensity pattern of a vortex beam acquires a form of dark stripes in the focal plane of a cylindrical lens. The number of the dark stripes is equal to the modulus of the vortex topological charge, while the stripe tilt indicates the charge sign. We demonstrate experimentally the effectiveness of this technique by revealing complex topological structure of polychromatic singular beams.6 pages"OSA will grant the authors permission to deposit the publisher’s pdf from their Optics Express articles into the repository with the proper citation (reference number or journal /volume/page/year citation)." - from email received from Authorized Agent, The Optical Society, 27/05/10Crystal optics, (260.6042) Singular optics2009-12-0710.1364/OE.17.0233742015-12-09