On tilt and curvature dependent errors and the calibration of coherence scanning interferometry

Su, Rong and Wang, Yuhang and Coupland, Jeremy and Leach, Richard K. (2017) On tilt and curvature dependent errors and the calibration of coherence scanning interferometry. Optics Express, 25 (4). pp. 3297-3310. ISSN 1094-4087

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Abstract

Although coherence scanning interferometry (CSI) is capable of measuring surface topography with sub-nanometre precision, it is well known that the performance of measuring instruments depends strongly on the local tilt and curvature of the sample surface. Based on 3D linear systems theory, however, a recent analysis of fringe generation in CSI provides a method to characterize the performance of surface measuring instruments and offers considerable insight into the origins of these errors. Furthermore, from the measurement of a precision sphere, a process to calibrate and partially correct instruments has been proposed. This paper presents, for the first time, a critical look at the calibration and correction process. Computational techniques are used to investigate the effects of radius error and measurement noise introduced during the calibration process for the measurement of spherical and sinusoidal profiles. Care is taken to illustrate the residual tilt and curvature dependent errors in a manner that will allow users to estimate measurement uncertainty. It is shown that by calibrating the instrument correctly and using appropriate methods to extract phase from the resulting fringes (such as frequency domain analysis), CSI is capable of measuring the topography of surfaces with varying tilt with sub nanometre accuracy.

Item Type: Article
Schools/Departments: University of Nottingham, UK > Faculty of Engineering
Identification Number: 10.1364/OE.25.003297
Depositing User: Eprints, Support
Date Deposited: 19 Jan 2017 13:35
Last Modified: 16 Oct 2017 15:12
URI: http://eprints.nottingham.ac.uk/id/eprint/39959

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