Applications of higher-order phase shifting algorithms for multiple-wavelength metrology

• Main Authors: Upputuri, Paul Kumar, Pramanik, Manojit
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2019
• Subjects: Engineering::Chemical engineering; Phase Shifting Interferometry; Multiple-wavelength
• Online Access: https://hdl.handle.net/10356/104906; http://hdl.handle.net/10220/49473
• Institution: Nanyang Technological University

Multiple-wavelength interferometric techniques have been successfully used for large step-height and large deformation measurements. Also it could resolve the step height between smooth and rough surfaces which is not possible with single wavelength interferometry. Temporal phase shifting algorithm, which requires a phase shifter such as PZT, has been widely used for accurate phase evolution in interferometry. The phase shifter needs to be calibrated at every wavelength if multiple wavelengths are used for measurement, it is a time consuming process. If phase shifter is not calibrated accurately, it can introduce phase shift errors. In this work, we will discuss various phase shifting algorithms, and their tolerance for phase shift error. And the applications of higher-order phased shifting algorithms will be presented. The study is useful for multiple-wavelength and white light interferometry where more than one wavelength is used for optical phase measurements.