Thomas Zeschke

Helmholtz-Zentrum Berlin für Materialien und Energie

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Frank Siewert

Helmholtz-Zentrum Berlin für Materialien und Energie

F. Senf

University of Potsdam

F. Eggenstein

Helmholtz-Zentrum Berlin für Materialien und Energie

Valeriy V. Yashchuk

Lawrence Berkeley National Laboratory

R. Follath

Paul Scherrer Institute

Heiner Lammert

Helmholtz-Zentrum Berlin für Materialien und Energie

Jana Buchheim

Helmholtz-Zentrum Berlin für Materialien und Energie

Tino Noll

Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy

Ralf D. Geckeler

Physikalisch-Technische Bundesanstalt

F. Schäfers

Albert Einstein College of Medicine

Cooperative Institutions

Helmholtz-Zentrum Berlin für Materialien und Energie

Deutsches Elektronen-Synchrotron DESY

Lawrence Berkeley National Laboratory

Universität Hamburg

Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy

Physikalisch-Technische Bundesanstalt

Berlin Schalltechnisches Büro

Paul Scherrer Institute

University of Potsdam

Centre National de la Recherche Scientifique

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Conception of diffractive wavefront correction for XUV and soft x-ray spectroscopy

Applied Optics (2020)

Jürgen Probst Christoph Braig Enrico Langlotz Ilko Rahneberg Michael Kühnel

We present a simple and precise method to minimize aberrations of mirror-based, wavelength-dispersive spectrometers for the extreme ultraviolet (XUV) and soft x-ray domain. The concept enables an enhanced resolving power E / Δ E , in particular, close to the diffraction limit over a spectral band of a few percent around the design energy of the instrument. Our optical element, the “diffractive wavefront corrector” (DWC), is individually shaped to the form and figure error of the mirror profile and might be written directly with a laser on a plane and even strongly curved substrates. Theory and simulations of various configurations, like Hettrick–Underwood or compact, highly efficient all-in-one setups for T i O 2 spectroscopy with E / Δ E ∼ x < 4.5 × 10 4 , are addressed, as well as aspects of their experimental realization.

Extreme ultraviolet

Soft X-rays

X-ray optics

Ptychography

X-Ray Spectroscopy

10.1364/ao.384782

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Citations (5)

Shape Optimization of High Performance X-Ray Optics

Springer eBooks (2008)

Frank Siewert Heiner Lammert Thomas Zeschke T. Hänsel Andreas Nickel

Figuring

X-ray optics

Root mean square

Line (geometry)

10.1007/978-3-540-74561-7_12

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Citations (1)

Optimized highly efficient multilayer-coated blazed gratings for the tender X-ray region

Optics Express (2019)

Andréy Sokolov Qiushi Huang F. Senf Jiangtao Feng Stephanie Lemke

The optimized design of multilayer-coated blazed gratings (MLBG) for high-flux tender X-ray monochromators was systematically studied by numerical simulations. The resulting correlation between the multilayer d-spacing and grating blaze angle significantly deviated from the one predicted by conventional equations. Three high line density gratings with different blaze angles were fabricated and coated by the same Cr/C multilayer. The MLBG with an optimal blaze angle of 1.0° showed a record efficiency reaching 60% at 3.1 keV and 4.1 keV. The measured efficiencies of all three gratings were consistent with calculated results proving the validity of the numerical simulation and indicating a more rigorous way to design the optimal MLBG structure.

Diffraction efficiency

10.1364/oe.27.016833

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Citations (30)

Surface Deformations of Optical Elements — An Investigation of Optical Systems Using the BESSY-NOM

AIP conference proceedings (2007)

Thomas Zeschke R. Follath Heiner Lammert F. Senf

The surface shape of optical elements is affected by their mounting (support, holder, clamping, cooling). The BESSY Nano Optic Measuring Machine (NOM) gives the opportunity to analyze these effects on the nanometer scale and sub‐nanometer scale. Linescans of surface profiles and the linescan‐based 3‐dimensional measurement feature of the NOM were used to characterize the surface shapes. In several configurations considering optical elements for the synchtrotron radiation application knowledge and effects about surface deformations due to mirror supports and coolings will be discussed. In this context a proposal for an adaptive mirror and the possible application in a BESSY‐beamline will be presented.

Nanometre

10.1063/1.2436153

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Citations (5)

Developmental long trace profiler using optimally aligned mirror based pentaprism

Lawrence Berkeley National Laboratory (2011)

Samuel K. Barber Gregory Y. Morrison Valeriy V. Yashchuk Mikhail V. Gubarev Ralf D. Geckeler

A low-budget surface slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought into operation at the Advanced Light Source Optical Metrology Laboratory. The instrument is based on a precisely calibrated autocollimator and a movable pentaprism. The capability of the DLTP to achieve sub-microradian surface slope metrology has been verified via cross-comparison measurements with other high-performance slope measuring instruments when measuring the same high-quality test optics. In the present work, a further improvement of the DLTP is achieved by replacing the existing bulk pentaprism with a specially designed mirror based pentaprism. A mirror based pentaprism offers the possibility to eliminate systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of a bulk pentaprism. We provide the details of the mirror based pentaprism design and describe an original experimental procedure for precision mutual alignment of the mirrors. The algorithm of the alignment procedure and its efficiency are verified with rigorous ray tracing simulations. Results of measurements of a spherically curved test mirror and a flat test mirror using the original bulk pentaprism are compared with measurements using the new mirror based pentaprism, demonstrating the improved performance.

Curved mirror

TRACE (psycholinguistics)

Source

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Citations (0)

Precision demanded of a Rowland circle monochromator: Its realization

Review of Scientific Instruments (1995)

F. Senf Heiner Lammert U. Flechsig Thomas Zeschke W. B. Peatman

A new monochromator design for high-energy resolution requires precise angle positioning of the grating during simultaneous linear motion of the grating vessel. The results obtained show that the required precision in the tilt angle of 0.05 arcsec can be met by the prototype of this monochromator. This is mainly achieved by a compensation of unavoidable systematic—time dependent and time independent—deviations from the ideal shape of the granite block on which an air bearing system moves. The compensation can be performed using the angle positioning system of the grating. The positioning accuracy here is better than 0.1 arcsec and shows a reproducibility of about 0.01 arcsec rms. The accuracy is provided by an angle encoder directly connected to the axis of rotation to be measured. A closed loop connection of the positioning and measuring system then allows a control on the grating angle within ± 0.03 arcsec. Thus, the mechanical precision made necessary by the use of the nearly perfect geometric surfaces of present day plane and spherical mirrors and gratings has been experimentally shown to be achievable.

Monochromator

Realization (probability)

Rotary encoder

Goniometer

10.1063/1.1145756

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Citations (7)

Survey and adjustment methods applied on an 11 axes high performance reflectometer for synchrotron radiation

AIP conference proceedings (2016)

F. Eggenstein Peter Bischoff F. Schäfers T. Schroeter F. Senf

At BESSY-II a new UV-and XUV optics beamline [1] has recently been setup with an in-house developed versatile reflectometer [2], [3], [4] for at-wavelength metrology on reflective and diffractive optical elements up to 4 kg mass. High precision measurements of the reflection and polarization properties are feasible by a 360° azimuthal rotation of the sample around the beam of light, where samples can be adjusted reproducibly with a novel UHV-Tripod within arc sec and μm precision. The azimuthal rotation requires an extremely high precision adjustment of the goniometer axis with respect to the incident light beam. Here we describe sophisticated methods with which we achieve nearly perfect agreement of the azimuthal rotation axis and the synchrotron beam in the 30 arc sec range. By using geodetic instruments (lasertracker, theodolite, autocollimator) the quality of the reflectometer UHV-mechanics has been characterized with respect to stiffness and radial run out with highest precision [5].

Achromatic lens

Goniometer

Theodolite

10.1063/1.4952848

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Citations (1)

Performance of the first undulator beamline U49-1-SGM at BESSY II

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment (2001)

F. Senf F. Eggenstein U. Flechsig R. Follath S. Hartlaub

Monochromator

Undulator

Photon energy

10.1016/s0168-9002(01)00372-2

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Citations (43)

Global High-Accuracy Intercomparison of Slope Measuring Instruments

AIP conference proceedings (2007)

Frank Siewert Lahsen Assoufid Daniele Cocco O. Hignette Steve C. Irick

The upcoming generation of high accuracy synchrotron radiation (SR) optics will be characterized by a slope deviation from ideal shape in the range of some 0.05μrad rms at a sampling interval of about 1mm. To certify and improve the measurement capabilities of metrology tools to inspect these stringent specifications, an essential step is a worldwide intercomparison of these measurements based on a set of transfer standards. It is the aim of these cross measurements to verify the “absolute” correctness and comparability of the measurement results obtained by the cooperating partners when measuring the topography of specific reference optics (ROs) using their latest metrology tools and methods. Organized by members of the SR‐optics community, new national and international cross measurement comparisons of typical synchrotron radiation mirrors have been realized during the last few years: A round robin test by the European COST‐program (BESSY, Elettra, ESRF, Soleil) during the years 2004–2005 and a similar cooperation realized by the APS, ESRF and Spring‐8 have proceeded. The first results of both projects were presented at the “Optics & Photonics” conference in San Diego in August 2005. This work build upon earlier work. The participants of both groups and representatives of other SR‐laboratories agreed to start a global cooperation bringing together the two round‐robin projects and open these activities to other partners from the SR‐community, optical manufacturers and other interested parties. This initiative is intended to start an extensive comparison of various measurement principles and tools and will help to push the frontiers in metrology, and hence production, to a precision well below the current state‐of‐the‐art limit of 0.5μrad rms for slope errors.

Comparability

10.1063/1.2436160

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Citations (9)

Highly efficient blazed grating with multilayer coating for tender X-ray energies

Optics Express (2016)

F. Senf F. Bijkerk F. Eggenstein Grzegorz Gwalt Qiushi Huang

For photon energies of 1 -5 keV, blazed gratings with multilayer coating are ideally suited for the suppression of stray and higher orders light in grating monochromators.We developed and characterized a blazed 2000 lines/mm grating coated with a 20 period Cr/C-multilayer.The multilayer d-spacing of 7.3 nm has been adapted to the line distance of 500 nm and the blaze angle of 0.84° in order to provide highest efficiency in the photon energy range between 1.5 keV and 3 keV.Efficiency of the multilayer grating as well as the reflectance of a witness multilayer which were coated simultaneously have been measured.An efficiency of 35% was measured at 2 keV while a maximum efficiency of 55% was achieved at 4 keV.In addition, a strong suppression of higher orders was observed which makes blazed multilayer gratings a favorable dispersing element also for the low X-ray energy range.

Diffraction efficiency

X-ray optics

Photon energy

Stray light

10.1364/oe.24.013220

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Citations (40)