HOLOGRAPHIC PHOTOELASTICITY: INFLUENCES OF INACCURACIES OF OPTICAL RETARDERS ON ISOCHROMATICS AND ISOPACHICS

In this paper the influence of inaccuracies of the optical retarders on the isochromatic and isopachic fringes obtained by holographic photoelasticity is studied. For the single-exposure hologram it is shown that the isochromatic visibility decreases as for light- and dark-field configurations, whereas the isochromatic fringes are distorted only for the dark-field configuration. For the double-exposure hologram it is shown that the isopachic fringes are generally distorted; with the isochromatics there is a decrease of fringe visibility. Experimental results confirming the theory are reported.