Comparison of the Moire Two-Beam Phase-Stepping and Fourier Transform Method techniques in Fizeau interferometry

摘要

We have previously proposed a phase evaluation method of multiple-beam Fizeau patterns that combines the two-beam phase-stepping algorithms with the moire effect. This method is based on a multiplicative moire image formation process obtained by the direct superposition of high-frequency multiple-beam Fizeau carrier fringes on a transmission grating (working as phase modulator). In this essay the contrast between this Moire Two-Beam Phase-Stepping technique and the direct evaluation of the high-frequency multiple-beam Fizeau carrier fringes by means of the Fourier Transform Method is presented.