Traceability in interferometric form metrology

Schulz, Michael; Blobel, G.; Fortmeier, Ines; Stavridis, Manuel; Elster, Clemens

doi:10.1117/12.2191136

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…The uncertainty in the wavelength seems unimportant to traceability. The phase calibration is of the essence to traceability and the measured surface is usually characterized relative to a standard surface which is used as the reference and should be calibrated with reversal techniques [39]. Schulz et al [40] analyzed the traceability route and evaluated the related uncertainties for surface interferometry.…”

Section: Traceability In Surface Interferometrymentioning

confidence: 99%

A review of interferometry for geometric measurement

Yang

Zhang

2018

Meas. Sci. Technol.

123

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As high-precision measuring instruments have developed, interferometers have been widely applied in the measurement of lengths and of the shape of surfaces, with nanometer precision. The emergence of the laser is one of the revolutions that has led to a well-defined traceability route to the definition of the meter via interferometry. Another change is the ever-increasing adoption of detector arrays substituting for conventional methods of recording and analyzing interferograms. New applications have also arisen from the adoption of microscopes, optical fibers, chip-level components and diffractive optical elements, developing enhanced analogues of conventional interferometers, which have the advantages of high integration, low noise levels, and complete sets of measuring instruments with a high level of automation. Since the requirements for measurement parameters and the environment are becoming more complex, we expect that the related instruments will play a progressively significant role in the progress of advanced manufacturing processes and quality control. Multi-sensor integrated flexible measurement methods have been proposed to perform measurements with holistic, more accurate and reliable information. However, most of the proposed methods are not intelligent and are highly integrated, providing only specific solutions for given measuring tasks. In this paper, the principles, progress, prospects and development trends of interferometry are reviewed.

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Section: Traceability In Surface Interferometrymentioning

confidence: 99%

A review of interferometry for geometric measurement

Yang

Zhang

2018

Meas. Sci. Technol.

123

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“…In 2011, the NMI of Germany, the Physikalisch-Technische Bundesanstalt (PTB), began to develop a metrological reference system for the optical form measurement of aspheres and freeform surfaces that would allow traceable, contact-free form measurements with low uncertainty in the range of some ten nanometers [7][8][9][10][11]. The system at PTB is based on the optical tilted-wave interferometer (TWI) proposed by scientists at the University of Stuttgart and further developed by them within the scope of different projects, as well as by PTB and Mahr GmbH.…”

Section: Introductionmentioning

confidence: 99%

Development of a metrological reference system for the form measurement of aspheres and freeform surfaces based on a tilted-wave interferometer

Fortmeier

Stavridis

Schulz

et al. 2022

Meas. Sci. Technol.

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Aspheres and freeform surfaces play an important role in today's optics industry. However, the measurement of such complex surfaces is still challenging even with state-of-the-art manufacturing technology, and there is an urgent need in industry for a non-contact, highly accurate reference measurement technique. To meet this demand, at PTB, a metrological reference system for the contact-free form measurement of aspheres and freeform surfaces is under development. The measurement system is based on a tilted-wave interferometer. Advances in computational capabilities have made it possible to solve the complex inverse problems associated with this measurement system and to develop sophisticated analysis procedures for reconstructing the surface under test from the measured interferogram data. In this paper, we will present the status of the tilted-wave interferometer-based measurement system at PTB, describe the analysis procedures we have designed and show initial measurement results. The benefit of the implementation presented here is that it allows insight to be gained into the performance of the measurement system and enables traceable measurements to be established with low uncertainty.

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“…One of the important parts of the project is the development and manufacturing of metrological reference surfaces. In the metrological traceability determination, the metrological reference surfaces (MRSs) are used to calibrate and verify aspherical and freeform metrology systems [5,6]. MRS application is following: after MRSs are designed and manufactured they are precisely characterized by different metrology institutes, stakeholders and other project partners and important data and deviations are derived from those measurements.…”

Section: Introductionmentioning

confidence: 99%

Influence of mounting on the optical surface figure in optical reference surfaces

et al. 2020

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The paper presents the effect of mechanical mounting of optical reference elements on their surface shape. Optical reference surfaces are key elements when traceable, highly accurate and precise optical surface measurements are required. In order to calibrate measuring instruments and compare the metrological capabilities of different metrology institutes, universities and other stakeholders, the reference artefacts were developed. Different measurement instruments require a different way of mounting and the reference artefacts are supposed to be useful for reliable and repeatable calibration of a great majority of the instruments worldwide. However, not only their shape was critical, but also the way of mounting was crucial. FEM analyses followed by experiments have revealed an unacceptable surface shape error in the order of hundreds of nanometres in the case of the commonly used screw mount, even for low applied torques. Other mounting options, such as the collet chuck or the Morse taper, are examined by means of FEM analysis and verified by interferometric measurements. It is shown that only the Morse taper can fulfil the strict criterion of less than 30 nm for surface shape deviation due to mounting, which is required in optical surface shape metrology.

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Traceability in interferometric form metrology

Cited by 4 publications

References 9 publications

A review of interferometry for geometric measurement

A review of interferometry for geometric measurement

Development of a metrological reference system for the form measurement of aspheres and freeform surfaces based on a tilted-wave interferometer

Influence of mounting on the optical surface figure in optical reference surfaces

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