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Mathematical Modelling and Data Analysis

Department 8.4

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Title: Absolute profile measurement of large moderately flat optical surfaces with high dynamic range
Author(s): A. Wiegmann, M. Schulz and C. Elster
Journal: Optics Express
Year: 2008
Volume: 16
Issue: 16
Pages: 11975
Optical Society of America
DOI: 10.1364/OE.16.011975
ISSN: 1094-4087
Web URL: http://www.osapublishing.org/viewmedia.cfm?uri=oe-16-16-11975&seq=0&html=true
Keywords: Image recognition,Instrumentation,Interferometry,Metrology,Surface measurements,algorithms and filters,and metrology,figure,measurement
Tags: 8.42, Form, SimOpt
Abstract: We present a novel procedure for absolute, highly-accurate profile measurement with high dynamic range for large, moderately flat optical surfaces. The profile is reconstructed from many sub-profiles measured by a small interferometer which is scanned along the specimen under test. Additional angular and lateral distance measurements are used to account for the tilt of the interferometer and its precise lateral location during the measurements. Accurate positioning of the interferometer is not required. The algorithm proposed for the analysis of the data allows systematic errors of the interferometer and height offsets of the scanning stage to be eliminated and it does not reduce the resolution. By utilizing a realistic simulation scenario we show that accuracies in the nanometer range can be reached.

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