  Based on spin-orbit coupling induced by q-plates, we present a feasible
experimental proposal for preparing two-dimensional spatially inhomogeneous
polarizations of light. We further investigate the quantum correlations between
these inhomogeneous polarizations of photon pairs generated by spontaneous
parametric down-conversion, which in essence describe the so-called
hypoentanglement that is established between composite spin-orbit variables of
photons. The violation of the Clauser-Horne-Shimony-Holt-Bell inequality is
predicted with S=2\sqrt2 to illustrate the entangled nature of the cylindrical
symmetry of spatially inhomogeneous polarizations.
