  A matrix representation is introduced for stationary beam-like light fields
that allows for simultaneous treatment of the orbital angular momentum (OAM)
and the second-order state of spatial coherence. This Coherence-OAM matrix is a
counterpart of the 2 x 2 beam Coherence-polarization matrix in a Cartesian
polarization basis or Coherence-spin angular momentum (SAM) matrix in a
circular polarization basis. The general properties of the Coherence-OAM matrix
are discussed and then the Coherence-SAM-OAM matrix is introduced as a unifying
entity for treating beams with any coherence, spin and orbital angular momentum
states.
