Improvements of measuring the width of Fraunhofer diffraction fringes using Fourier transform

Abstract In this paper, we proposed an improved method for calculating the fringe width of Fraunhofer diffraction. Because the diffraction patterns are equidistant when the diffraction angle is small, the width of fringes can be determined through finding out the spatial frequency of the fringes using Fourier transform. To make the result more precise, the experimental data are compared with the theoretical values having the same range of the image in the frequency domain to get the modified frequency. We applied this method to calculate the diameters of some filaments by measuring their Fraunhofer diffraction fringes.