DETERMINATION OF FRACTIONAL FRINGE ORDERS IN HOLOGRAPHIC-INTERFEROMETRY USING POLARIZATION PHASE-SHIFTING

A simple method to determine the fringe orders at points between fring es in holographic interferometry is presented. The method is based on the use of two reference beams in the recording and reconstruction of the interferogram. A phase difference is imposed between the reference beams on reconstruction through polarization elements. The interferog ram is viewed through a polarizer to recombine the images. The fractio nal fringe order is obtained from the angle through which the polarize r is rotated to shift the adjacent fringe to the point of interest.