Mr. Clemens Halbgewachs Profile

Clemens Halbgewachs

at Leibniz-Institut für Sonnenphysik (KIS)

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Author

Publications (10)

Proceedings Article | 9 August 2016 Paper

End-to-end simulations of the visible tunable filter for the Daniel K. Inouye Solar Telescope

Wolfgang Schmidt, Matthias Schubert, Monika Ellwarth, Jörg Baumgartner, Alexander Bell, Andreas Fischer, Clemens Halbgewachs, Frank Heidecke, Thomas Kentischer, Oskar von der Lühe, Thomas Scheiffelen, Michael Sigwarth

Proceedings Volume 9908, 99084N (2016) https://doi.org/10.1117/12.2232518

KEYWORDS: Tunable filters, Device simulation, Tunable filters, Fabry–Perot interferometers, Visible radiation, Solar telescopes, Magnetism, Modulation, Doppler effect, Iron, Calcium

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Proceedings Article | 9 August 2016 Paper

Qualification of HEIDENHAIN linear encoders for picometer resolution metrology in VTF Etalons

Clemens Halbgewachs, Thomas Kentischer, Karsten Sändig, Joerg Baumgartner, Alexander Bell, Andreas Fischer, Stefan Funk, Frank Heidecke, Thomas Scheiffelen, Wolfgang Schmidt, Erwin Spanner, Peter Speckbacher, Oskar von der Lühe

Proceedings Volume 9908, 99084H (2016) https://doi.org/10.1117/12.2232297

KEYWORDS: Metrology, Fabry–Perot interferometers, Computer programming, Sensors, Head, Fabry–Perot interferometers, Laser induced plasma spectroscopy, Temperature metrology, Control systems, Electronics, Actuators

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Proceedings Article | 9 August 2016 Paper

Development of high reflectivity coatings for large format Fabry-Perot etalons

M. Sigwarth, J. Baumgartner, A. Bell, G. Cagnoli, A. Fischer, C. Halbgewachs, F. Heidecke, Th. Kentischer, B. Kestner, P. Kuschnir, O. von der Lühe, L. Pinard, Ch. Michel, W. Reichman, B. Sassolas, Th. Scheiffelen, W. Schmidt

Proceedings Volume 9908, 99084F (2016) https://doi.org/10.1117/12.2232271

KEYWORDS: Fabry–Perot interferometers, Optical coatings, Reflectivity, Silica, Antireflective coatings, Prototyping, Annealing, Ion beam finishing, Thin film coatings, Polishing

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The Visible Tunable Filter (VTF) is a diffraction-limited narrowband tunable instrument for imaging spectropolarimetry in the wavelength range between 520 and 860 nm. It is based on large-format Fabry Perot. The instrument will be one of the first-light instruments of the 4m aperture Daniel K. Inoue Solar Telescope (DKIST). To provide a field of view of 1 arcmin and a spectral resolution λ/Δλ of about 100.000, the required free aperture of the Fabry Perot is 250mm. The high reflectivity coatings for the Etalon plates need to meet the specifications for the reflectivity over the entire wavelength range and preserve the plate figure specifications of better λ/300, and a micro roughness of < 0.4 nm rms. Coated surfaces with similar specifications have successfully been made for reflecting mirrors on thick substrates but not for larger format Fabry-Perot systems. Ion Beam Sputtering (IBS) based coatings provide stable, homogeneous, and smooth coatings. But IBS coatings also introduce stresses to the substrate that influence the plate figure in our case at the nm level. In a joint effort with an industry partner and a French CNRS research laboratory, we developed and tested processes on small and full size substrates, to provide coated Etalon plates to the required specifications. Zygo Extreme Precision Optics, Richmond, CA, USA, is polishing and figuring the substrates, doing the metrology and FE analysis. LMA (Laboratoire Matériaux Avancés, Lyon, France) is designing and making the IBS coatings and investigating the detailed behavior of the coatings and related processes. Both partners provide experience from manufacturing coated plane optics for gravitational wave detection experiments and EUV optics. The Kiepenheuer-Institut für Sonnenphysik, Freiburg, Germany is designing and building the VTF instrument and is leading the coating development. We present the characteristics of the coatings and the substrate processing concept, as well as results from tests on sample size and from full size substrate processing. We demonstrate that the tight specifications for a single Etalon can be reached.

Proceedings Article | 18 July 2014 Paper

DKIST visible tunable filter control software: connecting the DKIST framework to OPC UA

Alexander Bell, Clemens Halbgewachs, Thomas Kentischer, Wolfgang Schmidt, Oskar von der Lühe, Michael Sigwarth, Andreas Fischer

Proceedings Volume 9152, 91521D (2014) https://doi.org/10.1117/12.2055583

KEYWORDS: Control systems, Cameras, Optical proximity correction, Photonic integrated circuits, Modulators, Sensors, Fabry–Perot interferometers, Human-machine interfaces, Control systems design, OLE for process control

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Proceedings Article | 8 July 2014 Paper

A two-dimensional spectropolarimeter as a first-light instrument for the Daniel K. Inouye Solar Telescope

Wolfgang Schmidt, Alexander Bell, Clemens Halbgewachs, Frank Heidecke, Thomas Kentischer, Oskar von der Lühe, Thomas Scheiffelen, Michael Sigwarth

Proceedings Volume 9147, 91470E (2014) https://doi.org/10.1117/12.2056322

KEYWORDS: Fabry–Perot interferometers, Spectral resolution, Polarimetry, Telescopes, Coating, Signal to noise ratio, Sensors, Sun, Doppler effect, Polarization

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Proceedings Article | 24 September 2012 Paper

The visible tunable filtergraph for the ATST

T. Kentischer, W. Schmidt, O. von der Lühe, M. Sigwarth, A. Bell, C. Halbgewachs, A. Fischer

Proceedings Volume 8446, 844677 (2012) https://doi.org/10.1117/12.926789

KEYWORDS: Fabry–Perot interferometers, Signal to noise ratio, Reflectivity, Interferometers, Spectroscopy, Polarimetry, Spectral resolution, Collimation, Sun, Telescopes

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Proceedings Article | 28 July 2010 Paper

GREGOR telescope: start of commissioning

R. Volkmer, O. von der Lühe, C. Denker, S. Solanki, H. Balthasar, T. Berkefeld, P. Caligari, M. Collados, C. Halbgewachs, F. Heidecke, A. Hofmann, M. Klvana, F. Kneer, A. Lagg, E. Popow, D. Schmidt, W. Schmidt, M. Sobotka, D. Soltau, K. Strassmeier

Proceedings Volume 7733, 77330K (2010) https://doi.org/10.1117/12.857079

KEYWORDS: Mirrors, Telescopes, Adaptive optics, Cooling systems, Zerodur, Sun, Polarimetry, Solar telescopes, Coating, Visible radiation

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Proceedings Article | 21 July 2008 Paper

The control and data concept for the robotic solar telescope ChroTel

C. Halbgewachs, Ch. Bethge, P. Caligari, D. Elmore, T. Kentischer, H. Peter, M. Sigwarth, W. Schmidt

Proceedings Volume 7019, 70192T (2008) https://doi.org/10.1117/12.789114

KEYWORDS: Telescopes, Control systems, Cameras, Doppler effect, Sensors, Robotics, Image processing, Calcium, Data acquisition, Observatories

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Proceedings Article | 9 July 2008 Paper

ChroTel: a robotic telescope to observe the chromosphere of the Sun

T. Kentischer, Ch. Bethge, D. Elmore, R. Friedlein, C. Halbgewachs, M. Knölker, H. Peter, W. Schmidt, M. Sigwarth, K. Streander

Proceedings Volume 7014, 701413 (2008) https://doi.org/10.1117/12.789044

KEYWORDS: Telescopes, Optical filters, Mirrors, Sun, Lenses, Image filtering, Cameras, Robotics, Sensors, Charge-coupled devices

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Proceedings Article | 15 September 2005 Paper

The new 1.5 solar telescope GREGOR: progress report and results of performance tests

Reiner Volkmer, Oskar von der Lühe, Franz Kneer, Jürgen Staude, Thomas Berkefeld, Peter Caligari, Clemens Halbgewachs, Wolfgang Schmidt, Dirk Soltau, Harald Nicklas, Axel Wittmann, Horst Balthasar, Axel Hofmann, Klaus Strassmeier, Michal Sobotka, Miroslav Klvana, Manuel Collados

Proceedings Volume 5901, 590108 (2005) https://doi.org/10.1117/12.618247

KEYWORDS: Telescopes, Mirrors, Control systems, Space telescopes, Solar telescopes, Adaptive optics, Manufacturing, Optical alignment, Spectrographs, Deformable mirrors

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Showing 5 of 10 publications

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