Energy trajectories, that is, integral curves of the Poynting (current) vector, are calculated for scalar Bessel and Laguerre–Gauss beams carrying orbital angular momentum. The trajectories for the exact waves are helices, winding on cylinders for Bessel beams and hyperboloidal surfaces for Laguerre–Gauss beams. In the geometrical optics approximations, the trajectories for both types of beam are overlapping families of straight skew rays lying on hyperboloidal surfaces; the envelopes of the hyperboloids are the caustics: a cylinder for Bessel beams and two hyperboloids for Laguerre–Gauss beams.
|Translated title of the contribution||Exact and geometrical-optics energy trajectories in twisted beams|
|Pages (from-to)||035005-1 - 035005-7|
|Number of pages||7|
|Journal||Journal of Optics A: Pure and Applied Optics|
|Publication status||Published - Mar 2008|
Berry, MV., & McDonald, KT. (2008). Exact and geometrical-optics energy trajectories in twisted beams. Journal of Optics A: Pure and Applied Optics, 10, 035005-1 - 035005-7. https://doi.org/10.1088/1464-4258/10/3/035005