GENERATION OF THE DERIVATIVE OF OUT-OF-PLANE DISPLACEMENTS IN THE HIGH-SENSITIVITY GRATING INTERFEROMETRY CONFIGURATION

A simple method for determining the surface slope of a specimen under test in the high-sensitivity grating interferometry setup is proposed. The information on the derivative of out-of-plane displacement is obt ained by software subtraction of two primary interferograms: a convent ional one and one with diffraction orders laterally displaced in the i mage plane. Very good coincidence between the theoretical and experime ntal results has been obtained. The method can be used for studying st atic and transient events depending on the fringe pattern analysis met hod used. Copyright (C) 1996 Elsevier Science Ltd.