Coherent Optical Analog Computer for the Evaluation of Interferograms

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.