Phase shifting by a rotating polarizer in white-light interferometry for surface profiling

In white-light interferometry, the position of the peak of the fringe contr ast function is directly related to the surface height of the object. In th is paper, we present a phase-shifting technique to determine the fringe con trast function using a rotating polarizer, which introduces an achromatic p hase shift. The effect of introducing the rotating polarizer phase shifter at the output of the white-light interferometer has been studied. It is sho wn that the peak of the fringe contrast function does not occur for zero pa th difference between the arms of the interferometer; it is father shifted by a constant amount. This shift, however, does not introduce any error in relative height measurements. The experimental results are presented.