Dr. Thomas J. Kentischer Profile

Dr. Thomas J. Kentischer

at Leibniz-Institut für Sonnenphysik (KIS)

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Author

Publications (15)

Proceedings Article | 10 July 2018 Presentation + Paper

High uniformity IBS coatings for the world’s largest Fabry-Perot etalon of the VTF instrument

L. Pinard, C. Michel, B. Sassolas, J. Teillon, G. Cagnoli, M. Sigwarth, T. Kentischer, W. Schmidt, B. Reichman

Proceedings Volume 10706, 107061R (2018) https://doi.org/10.1117/12.2312007

KEYWORDS: Fabry–Perot interferometers, Mirrors, Optical coatings, Reflectivity, LIGO, Interferometers, Wavefronts, Absorption, Silica, Coating equipment

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SPIE Journal Paper | 2 November 2017 Open Access

Simulation algorithm to model the visible tunable filter for the Daniel K. Inouye Solar Telescope

Matthias Schubert, Thomas Kentischer, Oskar von der Lühe

JATIS, Vol. 3, Issue 04, 045002, (November 2017) https://doi.org/10.1117/12.10.1117/1.JATIS.3.4.045002

KEYWORDS: Computer simulations, Reflectivity, Fabry–Perot interferometers, Device simulation, Tunable filters, Algorithm development, Magnetism, Systems modeling, Solar telescopes, Sensors

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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 | 13 September 2012 Paper

Performance of a laser frequency comb calibration system with a high-resolution solar echelle spectrograph

H.-P. Doerr, T. Kentischer, T. Steinmetz, R. Probst, M. Franz, R. Holzwarth, Th. Udem, T. W. Hänsch, W. Schmidt

Proceedings Volume 8450, 84501G (2012) https://doi.org/10.1117/12.926224

KEYWORDS: Calibration, Spectrographs, Frequency combs, Telescopes, Charge-coupled devices, Spectral calibration, Cameras, Space telescopes, Point spread functions, Spectral resolution

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Proceedings Article | 21 July 2010 Paper

The polarization optics for the European Solar Telescope (EST)

F. C. Bettonvil, M. Collados, A. Feller, B. Gelly, C. Keller, T. Kentischer, A. López Ariste, O. Pleier, F. Snik, H. Socas-Navarro

Proceedings Volume 7735, 77356I (2010) https://doi.org/10.1117/12.857817

KEYWORDS: Polarization, Polarimetry, Calibration, Modulators, Mirrors, Telescopes, Adaptive optics, Optical coatings, Solar telescopes, Silver

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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 | 9 July 2008 Paper

Polarization effects in Fabry-Pérot interferometer-based solar spectrometers

H.-P. Doerr, O. von der Lühe, T. Kentischer

Proceedings Volume 7014, 701417 (2008) https://doi.org/10.1117/12.789180

KEYWORDS: Polarization, Fabry–Perot interferometers, Point spread functions, Polarimetry, Interferometers, Reflection, Spectrometers, Multilayers, Reflectivity, Collimation

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Proceedings Article | 27 June 2006 Paper

Auto alignment and image tracking system for the SUNRISE telescope

W. Schmidt, T. Berkefeld, B. Feger, R. Friedlein, K. Gerber, F. Heidecke, T. Kentischer, O. v. d. Lühe, M. Sigwarth, D. Soltau, E. Wälde

Proceedings Volume 6274, 62740H (2006) https://doi.org/10.1117/12.669955

KEYWORDS: Telescopes, Adaptive optics, Mirrors, Sun, Monochromatic aberrations, Wavefront sensors, Servomechanisms, Sensors, Cameras

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Proceedings Article | 28 September 2004 Paper

High-precision wavefront sensor for the SUNRISE Telescope

Wolfgang Schmidt, Thomas Berkefeld, Ruediger Friedlein, Frank Heidecke, Thomas Kentischer, Oskar von der Luhe, Michael Sigwarth, Dirk Soltau, E. Walde

Proceedings Volume 5489, (2004) https://doi.org/10.1117/12.549769

KEYWORDS: Telescopes, Mirrors, Wavefront sensors, Calibration, Sun, Monochromatic aberrations, Sensors, Wavefronts, Motion measurement

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Showing 5 of 15 publications

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