Optical spin-orbit interaction induced by magnetic textures

Contrary to the optical spin angular momentum (SAM), the role played by the orbital angular momentum (OAM) of light in magneto-optics remains largely unexplored. However, the SAM and OAM are known to be coupled when light interacts with non-homogeneous and non-isotropic materials. Here we predict that the OAM carried by each photon in a light beam is modified upon reflection on magnetic textures like skyrmions, and that the sign and magnitude of this variation are governed both by the SAM of the incident field and by the topology of the texture. Our predictions can be readily tested by performing circular dichroism measurements, and may provide new routes to read the topology of magnetization optically, or to shape light's angular momentum with magnetism.