Optical angular momentum in dispersive media

Abstract

The angular momentum density and flux of light in a dispersive, rotationally symmetric medium are derived from Noether's theorem. Optical angular momentum in a dispersive medium has no simple relation to optical linear momentum, even if the medium is homogeneous. A circularly polarized monochromatic beam in a homogeneous, dispersive medium carries a spin angular momentum of $\ifmmode\pm\else\textpm\fi{}\ensuremath{\hbar}$ per energy $\ensuremath{\hbar}\ensuremath{\omega}$, as in vacuum. This result demonstrates the nontrivial interplay of dispersive contributions to optical angular momentum and energy.