Relevance of longitudinal fields of paraxial optical vortices

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Longitudinal electromagnetic fields generally become comparable with the usually dominant transverse components in strongly focused, non-paraxial beams. For paraxial optical vortex modes it is highlighted here how their angular momentum properties produce longitudinal fields that in general must be accounted for. First-order longitudinal components of quantized Laguerre–Gaussian modes are derived and numerically studied with respect to the paraxial parameter, highlighting light-matter and spin-orbit interactions that stem from the longitudinal fields of paraxial beams in free space. New restrictions are cast on the validity of neglecting longitudinal fields for paraxial optical vortices interacting with atoms, molecules and other nanostructures.

Original languageEnglish
Article number075401
JournalJournal of Optics
Issue number7
Early online date28 May 2021
Publication statusPublished - Jul 2021


  • Optical orbital angular momentum
  • Optical vortices
  • Paraxial optics
  • Quantum electrodynamics
  • Spin–orbit interaction of light
  • Structured light

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