Surface Topography of Transparent Plate Using Fizeau Interferometer with Suppression of Intensity Modulation

Abstract

The derivation of 19-fringe phase-modulated algorithm that can suppress the first order nonlinear intensity modulation during wavelength modulating is presented. We visualize the proposed algorithm in the frequency domain in connection with the Fourier representation to discuss the properties of the algorithm. The 19-fringe algorithm yields the smallest phase error compared to the conventional algorithms. Lastly, we assess the surface of the transparent fused silica plate using the wavelength-modulating Fizeau interferometer and the 19-fringe algorithm. From the experiment results, it is indicated that the accuracy of the surface assessment for the fused silica plate is 4.0 nm.