The Photon Hall Pinwheel, Radiation of Angular Momentum by a Diffusing Magneto-optical Medium

Abstract

We consider an optically thick spherical agglomerate of magneto-optical scatterers with a central isotropic, unpolarized light source, placed in a homogeneous magnetic field. The Photon Hall Effect induces a rotating Poynting vector, both inside and outside the medium. We show that electromagnetic (orbital) angular momentum leaks out and induces a torque proportional to the injection power of the source and the photon Hall angle. This effect represents a novel class of optical phenomena, generating angular momentum from diffusive magneto-transport.