A method for the Fourier transformation of one-dimensional functions, especially interferograms, with coherent light is described. The functions to be transformed are represented in the form of transparent masks with amplitude transmittance T = ± 1. Negative values of amplitude transmittance are realized with a phase plate. As the essential result, the Fourier transform of the interferogram is displayed by a lens along the abscissa of the frequency plane.
F. LANZL, H. J. MAGER, and W. WAIDELICH, "Coherent Optical Analog Computer for the Evaluation of Interferograms," J. Opt. Soc. Am. 61, 1355-1358 (1971)