Measurement of the coherence-OAM polarization matrix of a partially coherent vector light beam.

The second-order correlations of two orbital angular momentum (OAM) modes contained in a partially coherent vector light beam exhibit rich polarization-like geometric structures. In this Letter, we present a general method to measure the coherence-OAM-polarization (COAMP) matrix of such a beam, revealing OAM-resolved polarization properties. The principle of our method is thoroughly discussed and validated in the proof-of-principle experiment. The OAM-resolved generalized Stokes parameters and degree of polarization of an electromagnetic Gaussian Schell-model source are retrieved from the measured COAMP matrix and analyzed in detail. Our protocol paves the way for exploiting OAM-resolved polarization properties in optical sensing, imaging, and information processing.