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arXiv · 2005.02739

Angular momentum conservation in counter-propagating vectorially structured light

Hang Li·Valeria Rodriguez-Fajardo·Peifeng Chen·Andrew Forbes
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Abstract

It is well-known that electric spin angular momentum and electric orbital angular momentum are conserved under paraxial propagation of travelling waves in free-space. Here we study the electric and magnetic angular momentum in counter-propagating waves and show both theoretically and experimentally that neither component alone is conserved except in special cases. We attribute this non-conservation to spin-spin and orbit-orbit coupling between the electric and magnetic fields. This work generalises previous findings based on travelling waves, explains the apparent spin-orbit coupling in counter-propagating paraxial light, and broadens our understanding of angular momentum conservation in arbitrary structured light waves.

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Hang Li, Valeria Rodriguez-Fajardo, Peifeng Chen, Andrew Forbes. 2020-05-06. Angular momentum conservation in counter-propagating vectorially structured light. https://doi.org/10.1103/physreva.102.063533

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