Rotation of electromagnetic fields and the nature of optical angular momentum

Stephen M. Barnett

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The association of spin and orbital angular momenta of light with its polarization and helical phase fronts is now well established. The problems in linking this with electromagnetic theory, as expressed in Maxwell's equations, are rather less well known. We present a simple analysis of the problems involved in defining spin and orbital angular momenta for electromagnetic fields and discuss some of the remaining challenges. Crucial to our investigation is the duplex symmetry between the electric and magnetic fields.

Original languageEnglish
Pages (from-to)1339-1343
Number of pages5
JournalJournal of Modern Optics
Issue number14-15
Early online date9 Mar 2010
Publication statusPublished - Aug 2010


  • optical angular momentum
  • light
  • radiation
  • beams
  • spin

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