Short-periodic measuring of great retardations with a modified Senarmont-method

Up to now measurements of retardations and of birefringence on flexible, anisotropic media (fibres, films) are done contactlessly, automatically and on-line. For new manufacturing processes of such media first of all fast (short-periodic) and free of false colours measurements are required for very large retardations. A simultaneous combination of the multicolour-Senarmont-method with the discrete Fourier-Analysis (DFA) is presented in this paper.