Concept, design and capability analysis of the new Deflectometric Flatness Reference at PTB

Schulz, Michael; Ehret, Gerd; Stavridis, Manuel; Elster, Clemens

doi:10.1016/j.nima.2009.10.108

Cited by 21 publications

(17 citation statements)

References 6 publications

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“…at PTB to overcome this shortcoming. [ 215 ] One is used to measure the surface slope with a scanning penta‐prism, and the other is used to measure the tilt angle of the test surface. The test surface is no longer stationary but tilted at different scanning points so as to minimize the beam lateral motion induced by the surface slope.…”

Section: Single‐point‐probe‐based Profilometrymentioning

confidence: 99%

Measurement of Freeform Optical Surfaces: Trade‐Off between Accuracy and Dynamic Range

Chen

Xue

Zhai

et al. 2020

Laser & Photonics Reviews

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Freeform optical surfaces are advantageous to optical designers, as they provide additional degrees of freedom for optimization. The loss of rotational symmetry, however, makes measurement of freeforms more challenging. Herein, advances in interferometric areal measurement of freeform optical surfaces, including null tests, non-null tests, near-null tests, and adaptive null tests, are reviewed. Some new developments, in the Hartmann test, deflectometry, and phase retrieval, as representatives of non-interferometric areal measurement, are then presented. Overall, the focus is on single-point-probe-based profilometry categorized into coordinate measurements and slope-or curvature-based measurements. Innovative measurement technology is trying to bridge the gap between high accuracy and high dynamic range as freeform optical surfaces are finding more applications in visible and shorter-wavelength optics.

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Section: Single‐point‐probe‐based Profilometrymentioning

confidence: 99%

Measurement of Freeform Optical Surfaces: Trade‐Off between Accuracy and Dynamic Range

Chen

Xue

Zhai

et al. 2020

Laser & Photonics Reviews

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“…Instruments like the Long Trace Profiler (LTP) [23,25], the Deflectometric Flatness Reference (DFR) [26,27,28] or the Nanometer Optical Component Measuring Machine [29,30] enable the inspection of reflective free form surfaces by a direct measurement of the deflection angle of a laser beam. The classical LTP-II as provided first by Continental Optics Ltd. was enabling an accuracy of 0.5 µrad rms for a slope measurement.…”

Section: Slope Measuring Instruments In Use For the Inspection Of Synmentioning

confidence: 99%

“…The NOM is a hybrid of a LTPhead, designed by Peter Takacs and an autocollimator made by Möller Wedel Optical GmbH. Enabling an accuracy of 0.05 µrad rms for plane and slightly curved optics the BESSY-NOM represents a 2nd generation slope measuring profiler [26,27,28,37]. Further NOM or NOM-like instruments have been commissioned recently at Diamond Light Source (UK) [38], ALBA Synchrotron (Spain) [39], APS-Advanced Photon Source (USA) [40,41], NSLS-II (USA) [42] and at the LBNL / ALS -Optics and Metrology Lab in Berkeley (USA) [43].…”

Section: Slope Measuring Instruments In Use For the Inspection Of Synmentioning

confidence: 99%

Pushing the limits: latest developments in angle metrology for the inspection of ultra-precise synchrotron optics

2014

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The requirements on the quality of ultra-precise X-ray optical components for application in the Synchrotron Radiation (SR) community are increasing continually and strongly depend on the quality of the metrology devices available to measure such optics. To meet the upcoming accuracy goal of 50 nrad rms for slope measuring profilers, a dedicated project, SIB58 Angles, consisting of 16 worldwide partners and supported by the European Metrology Research Programme (EMRP) was started in Sep 2013. The project covers investigations on autocollimators under extremely challenging measuring conditions, ray-tracing models, 2D autocollimator calibration (for the first time worldwide), determination of error sources in angle encoders providing traceability by 'sub-division of 2π rad' with nrad uncertainty, angle generation by 'ratio of two lengths' in nrad level, and on the development of portable precise Small Angle Generators (SAGs) for regular in-situ checks of autocollimators' performance. Highlights from the project will be reported in the paper and the community of metrology for X-Ray and EUV Optics will be informed about its progress and the latest work in angle metrology.

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“…The computer model is implemented in MATLAB, which is a widespread tool for modeling and prototyping in the scientific community. It supports object-oriented programming approaches, which allow the modeling of a measuring system in a flexible way for various applications [23][24][25][26][27][28].…”

Section: Computer Modelingmentioning

confidence: 99%

Virtual experiment for near-field goniophotometric measurements

et al. 2014

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Near-field goniometric measurements are employed to determine the photometric characteristics of light sources, i.e., the spatial and angular distribution of the emitted light. To this end, a complex measurement system consisting of a goniometer and a CCD-based imaging photometer is employed. In order to gain insight into the measurement system and to enable characterization of the whole measurement setup, we propose to apply a computer model to conduct virtual experiments. Within the computer model, the current state of all parts of the virtual experiment can be easily controlled. The reliability of the computer model is demonstrated by a comparison to actual measurement results. As an example for the application of the virtual experiment, we present an analysis of the impact of axial malpositions of the goniometer and camera.

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Concept, design and capability analysis of the new Deflectometric Flatness Reference at PTB

Cited by 21 publications

References 6 publications

Measurement of Freeform Optical Surfaces: Trade‐Off between Accuracy and Dynamic Range

Measurement of Freeform Optical Surfaces: Trade‐Off between Accuracy and Dynamic Range

Pushing the limits: latest developments in angle metrology for the inspection of ultra-precise synchrotron optics

Virtual experiment for near-field goniophotometric measurements

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