FRINGE FORMATION IN SYMMETRICAL 3-APERTURE SPECKLE SHEAR INTERFEROMETRY - AN ANALYSIS

Multi-aperture speckle shear interferometry also exhibits sensitivity to the in-plane displacement component. The interferogram obtained eve n at normal illumination contains fringes due to the combined contribu tions of slope, strain and in-plane components. The fringe pattern, th erefore, changes when the shear element is placed at different apertur e positions for the same experimental conditions. We have examined a t hree-aperture symmetric configuration where the shear element is eithe r placed at the peripheral aperture or at the central aperture. The ex perimental results are presented. Copyright (C) 1996 Elsevier Science Ltd.