Wave dislocation line threaded polarization interferometer

Constructing a closed-circuit polarization interferometer, wherein a wave dislocation line can be visualized to thread the parameter space, is a topic of fundamental and applied research interest. Proposed by Berry [Proc. R. Soc. A463, 1697 (2007)10.1098/rspa.2007.1842] in the scalar wave domain, this universal phenomenon is simulated and experimentally demonstrated in the vector domain using a rotated-tilted quartz crystal plate in a polarization interferometer. The phase difference between overlapping ordinary and extraordinary paraxial ray beams passing through the crystal plate is varied continuously. The appearance of ±1 dislocation number spiral- and saddle-type topological structures in the complex Stokes phase is a result of satisfying ± π/2 phase difference between the ray beams and around the zero-crossings of the Stokes parameters.