Angular momentum conservation in partially coherent wave fields

Abstract

Angular momentum in electromagnetic wave systems is an important yet difficult subject to deal with, both classically and quantum mechanically. We investigate the angular momentum of partially coherent electromagnetic wave fields and establish the general formalism for angular momentum conservation, based on the Maxwell stress tensor for partially coherent sources and fields in the space-frequency domain. This formalism is applied to study the angular momentum properties of several classes of partially coherent electromagnetic beams possessing circulation.