Rotatable single wedge plate shearing interference technique for collimation testing

We describe the basic theory and technique of a collimation testing method based on analysis of the lateral shearing interference fringe. The changed fringe spacing and the orientation after rotation of a single wedge plate through 180 deg. indicate the degree of collimation of the light beam. The preliminary experimental equipment is described, precision analyses are presented, and the usefulness for practical applications is demonstrated.