Improving the Reliability of Interference Measurements by using Several Wavelengths

Abstract

Methods are proposed to improve the reliability of interference measurements of surface nanotopography with sharp height gradients that lead to ambiguity in determining the phase of interference signals. The effect of the total measurement error on the range of multiwavelength measurements is considered. The results of field experiments demonstrating an increase in the range of measurements of nanotopography by the proposed methods in comparison with single-wavelength measurements are given.