  We discuss the effects of a direct coupling between a rank-two antisymmetric
tensor field and the Maxwell field. The coupling we consider leads to vacuum
birefringence, allowing us to place constraints on the magnitude of the tensor
field and the strength of its coupling to the Maxwell field via cosmological
birefringence measurements. For light propagating in the presence of a
topological defect solution, we find that light rays with different
polarizations will follow different trajectories; the magnitude of this
deflection is predicted to be extremely small (on the order of 10^-10
arcseconds). We discuss the plausibility of this phenomenon as a method for
detection of these monopoles, along with the applicability of our methods to
other possible couplings between the tensor field and the Maxwell field.
