Van Cittert-Zernike theorem with Stokes parameters.

We formulate the van Cittert-Zernike theorem for spatially incoherent partially polarized sources in terms of the traditional polarization (one-point) Stokes parameters and the coherence (two-point) Stokes parameters. This leads to a physically insightful connection between the source polarization and the field coherence. We show that the far-zone coherence is given by a Fourier relation of the source-plane polarization and apply the results to investigate the far-zone properties of a field emitted by an incoherent source limited by an annular aperture.