title: Van Cittert-Zernike theorem and symmetry properties of the normalized cross-spectral density matrix.
abstract: The van Cittert-Zernike theorem is formulated for the normalized cross-spectral density matrix of fields emitted by spatially incoherent sources. This formulation shows that sources with homogeneous polarization characteristics at second-order lead in the far field to normalized cross-spectral density matrices that possess high-symmetry properties. These symmetry properties are lost with polarization inhomogeneities of the source. These results are illustrated with ring-shaped sources.
authors.forename: Philippe
authors.initials: P
authors.lastname: Réfrégier
authors.forename: Antoine
authors.initials: A
authors.lastname: Roueff
authors.forename: Valentine
authors.initials: V
authors.lastname: Wasik