Approaching sub-50 nanoradian measurements by reducing the saw-tooth deviation of the autocollimator in the Nano-Optic-Measuring Machine

Qian, Shen‐En; Geckeler, Ralf D.; Just, A.; Idir, Mourad; Wu, Xiang

doi:10.1016/j.nima.2015.02.065

Cited by 30 publications

(28 citation statements)

References 13 publications

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“…The most important are larger distances that correspond to the AC optical beam path present in a NOM-like profilometer with a stationary AC and a movable pentaprism. 3,4,[6][7][8][9][10][11] In this case, we should expect a higher level of spurious effect due to AC light diffraction on the aperture. The shorter distances are interesting for the applications in surface slope profilers with a movable AC.…”

Section: Aperture Systems With Adjustable Dimensionsmentioning

confidence: 99%

“…5 A large number of optical metrology labs at synchrotron and free electron laser x-ray facilities have AC-based profilometers in different arrangements. [6][7][8][9][10][11][12] These tools have proven capable of characterizing modern aspherical x-ray optics with an accuracy of the level of 100 nrad (root-mean-square, rms) over the spatial wavelength range limited by the size of the AC light beam aperture used and the maximum scanning length of the profilometer. In the case of shorter mirror lengths (<200 mm), mirrors with slope error better than 50 nrad (rms) have been measured.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of the size and shape of the scanning aperture in autocollimator-based deflectometric profilometers

Lacey

Geckler

Just

et al. 2019

Review of Scientific Instruments

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Section: Aperture Systems With Adjustable Dimensionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization of the size and shape of the scanning aperture in autocollimator-based deflectometric profilometers

Lacey

Geckler

Just

et al. 2019

Review of Scientific Instruments

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“…There is also a contribution of the aliasing effect due to sampling period different from the angular period of the 13-µrad quasi-periodic error of the AC. For the AC-based profilometer measurements without a high-angular-resolution calibrations, the later factor sets a principle limitation to the random-looking error of the measurements [46]. In order to make the calibration free of the random error, we use the resulted fitting function (corresponding to Fig.…”

Section: In-situ Angular Calibration Of the Tilt Stagementioning

confidence: 99%

Transfer of autocollimator calibration for use with scanning gantry profilometers for accurate determination of surface slope and curvature of state-of-the-art x-ray mirrors

Lacey

Anderson

Dickert

et al. 2019

Advances in Metrology for X-Ray and EUV Optics VIII

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X-ray optics, desired for beamlines at free-electron-laser and diffraction-limited-storage-ring x-ray light sources, must have almost perfect surfaces, capable of delivering light to experiments without significant degradation of brightness and coherence. To accurately characterize such optics at an optical metrology lab, two basic types of surface slope profilometers are used: the long trace profilers (LTPs) and nanometer optical measuring (NOM) like angular deflectometers, based on electronic autocollimator (AC) ELCOMAT-3000. The inherent systematic errors of the instrument's optical sensors set the principle limit to their measuring performance. Where autocollimator of a NOM-like profiler may be calibrated at a unique dedicated facility, this is for a particular configuration of distance, aperture size, and angular range that does not always match the exact use in a scanning measurement with the profiler. Here we discuss the developed methodology, experimental setup , and numerical methods of transferring the calibration of one reference AC to the scanning AC of the Optical Surface Measuring System (OSMS), recently brought to operation at the ALS X˗Ray Optics Laboratory. We show that precision calibration of the OSMS performed in three steps, allows us to provide high confidence and accuracy low-spatial-frequency metrology and not 'print into' measurements the inherent systematic error of tool in use. With the examples of the OSMS measurements with a state-of-the-art x-ray aspherical mirror, available from one of the most advanced vendors of x˗ray optics, we demonstrate the high efficacy of the developed calibration procedure. The results of our work are important for obtaining high reliability data, needed for sophisticated numerical simulations of beamline performance and optimization of beamline usage of the optics.

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“…12,27,[37][38][39][40][41] This can be thought of as a repeatability ( Below we describe a custom-made tilt stage Model N-310K021 designed and manufactured at Physik…”

Section: Design and Compliance Tests Of A Tilt Stage For A Utm Smentioning

confidence: 99%

High precision tilt stage as a key element to a universal test mirror for characterization and calibration of slope measuring instruments

Yashchuk

Artemiev

Centers

et al. 2016

Review of Scientific Instruments

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The ultimate performance of surface slope metrology instrumentation, such as long trace profilers and autocollimator based deflectometers, is limited by systematic errors that are increased when the entire angular range is used for metrology of significantly curved optics. At the ALS X-Ray Optics Laboratory, in collaboration with the HZB/BESSY-II and PTB (Germany) metrology teams, we are working on a calibration method for deflectometers, based on a concept of a universal test mirror (UTM) [Proc. SPIE 6704, 67040A (2007)]. Potentially, the UTM method provides high performance calibration, and accounts for peculiarities of the optics under test (e.g., slope distribution) and the experimental arrangement (e.g., the distance between the sensor and the optic under test). At the same time, the UTM calibration method is inherently universal, applicable to a variety of optics and experimental arrangements. In this work we present the results of tests with a key component of the UTM system, a custom high precision tilt stage, which has been recently developed in collaboration with Physik Instrumente, a Author to whom correspondence should be addressed. Electronic mail: VVYashchuk@lbl.gov. 2GmbH. The tests have demonstrated high performance of the stage and its capability (after additional calibration) to provide angular calibration of surface slope measuring profilers over the entire instrumental dynamic range with absolute accuracy better than 30 nrad. The details of the stage design and tests are presented. We also discuss the foundation of the UTM method and calibration algorithm, as well as the possible design of a full scale UTM system.

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Approaching sub-50 nanoradian measurements by reducing the saw-tooth deviation of the autocollimator in the Nano-Optic-Measuring Machine

Cited by 30 publications

References 13 publications

Optimization of the size and shape of the scanning aperture in autocollimator-based deflectometric profilometers

Optimization of the size and shape of the scanning aperture in autocollimator-based deflectometric profilometers

Transfer of autocollimator calibration for use with scanning gantry profilometers for accurate determination of surface slope and curvature of state-of-the-art x-ray mirrors

High precision tilt stage as a key element to a universal test mirror for characterization and calibration of slope measuring instruments

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