Influence of the defect in the contour line of the multiple-beam Fizeau fringes on the determination of the optical and some structural properties of polyethylene fiber

A simulated interferograms of multiple-beam interference Fizeau fringes (in transmission) and a modeling equation which simulates the phase modulation of polyethylene fiber (HDPE fiber) with different draw ratios were presented. As far as we know, this is the first time that a modeling equation has been presented that simulates the multiple-beam Fizeau interferograms for drawing polyethylene fibers with different draw ratios. The interferograms were analyzed using all the peaks of Fourier transform (FT) spectra. The peaks of the FT spectra play an important role in the precision of analyzing the interferograms and in the precision of the obtained contour lines of the fringes. The influence of the peaks of the FT spectra on the fringe shift inside the fiber, the refractive indices, the birefringence, the orientation function, the polarizability per unit volume, and other structural parameters of drawing polyethylene fiber were examined. The comparison between the outcomes in the situation of the first peak and all the peaks of FT spectra was given. The calculated results from the presented modeling equation are in agreement with the published experimental results of the drawing polyethylene fiber. For more explanation, simulated interferograms, tables, and figures are presented.