Polarization phase stepping with a savart element

The imaging properties of a real-time shearing interferometer are presented. The use of Savart elements, both as a beam displacer and an analyzer in a polarization phase-stepping scheme, is demonstrated in a real-time, two-camera, four-bucket shearing interferometer. A simple calculation scheme for ray propagation through uniaxial, birefringent elements is presented, and the effects on the image formation through 6-cm-long Savart elements is discussed.