A MEASURING METHOD OF A CONCAVE MIRROR BY DEFOCUSING A SCATTER PLATE

Abstract

Based on the fact that the phase variation is linearly proportional to the defocusing amount of the scatter plate, the additional phase shift can be achieved by defocusing the scatter plate in a controlled manner. Consequently, a method of how the phase shifting interferometric technique can be applied to the scatter plate interferometer is described. It has both the merits of a conventional scatter plate interferometer and the phase shifting interferometric technique. The validity of this method is demonstrated.