Shearograms of a singular beam using wedge plate lateral shear interferometer

Shearograms of a phase singular beam obtained with a wedge plate lateral shear interferometer are presented. Unlike a normal lateral shear interferometer, a wedge plate lateral shear interferometer generates fork fringes, even in the absence of curvature in a phase singular beam. Thus, a wedge plate lateral shear interferometer is a more effective tool for the detection of optical vortices. Shearograms are recorded and analyzed for three separate cases: when the tilt and shear are in same direction, in opposite direction and when the two are normal to each other. It is shown that when tilt is normal to the direction of shear, the interferometer can be used for testing collimation of singular beams.