Fourier interferometry of multi-layer sample using wavelength tuning and partially negative window. (February 2021)

• Record Type: Journal Article
• Authors: Kim, Yangjin; Bae, Wonjun; Moon, Young Hoon; Hibino, Kenichi; Mitsuishi, Mamoru
• Is Part Of: Optics and lasers in engineering. Volume 137(2021)
• Publication Date: 2021-02
• Subjects: Fizeau interferometer -- Simultaneous measurement -- Surface profile -- Thickness -- Window function; Lasers in engineering -- Periodicals; Optical measurements -- Periodicals; Optics -- Periodicals; Lasers en ingénierie -- Périodiques; Mesures optiques -- Périodiques; Optique -- Périodiques; 621.36605
• DOI: 10.1016/j.optlaseng.2020.106350
• Languages: English
• ISSNs: 0143-8166

Abstract

Highlights: Formulation of bias phase error occurring during wavelength tuning. Development of 4 N – 1 algorithm that can eliminate the bias phase error. Numerical error analysis of 4 N – 1 algorithm with comparisons to other algorithms. Measurement of thickness and surface of LNB wafer using 4 N – 1 algorithm and Fizeau interferometer. Abstract: When measuring the thickness of a transparent plate using wavelength tuning-based phase modulation fringe analysis, the nonlinearity of the phase modulation can cause both a nonuniform phase error and a bias phase error. In this study, a method of eliminating the bias phase error using the characteristic polynomial theory was developed and a flexible 4 N − 1 algorithm, consisting of a partially negative window and a discrete Fourier transform term, was constructed. The behaviors of the 4 N − 1 algorithm were visualized in the frequency domain. The error compensation ability was estimated by comparing it to conventional algorithms. The thickness and surface profile of a lithium niobate wafer were simultaneously measured using a Fizeau interferometer and the proposed 4 N − 1 algorithm. The experimental results showed that the 4 N − 1 algorithm performs better than other algorithms in terms of the repeatability error and suppression of the bias phase error.