Dr. Torsten Diehl Profile

Dr. Torsten Diehl

Head of Field of Business at Carl Zeiss Spectroscopy GmbH

SPIE Involvement:

Author

Area of Expertise:

Optics , Gratings , Spectrometer , Spectroscopy , Product Management

Publications (10)

Proceedings Article | 10 October 2019 Paper

Manufacturing method for monolithic freeform Offner-gratings for hyper-spectral imaging

M. Burkhardt, T. Rathje, D. Lehr, L. Erdmann, M. Helgert, P. Triebel, T. Diehl, A. Gatto, N v.d Valk, R. Vink, R. Jansen, J. Day, W. Gielesen

Proceedings Volume 11151, 111510U (2019) https://doi.org/10.1117/12.2532101

KEYWORDS: Manufacturing, Diffraction gratings, Hyperspectral systems, Optics manufacturing, Optical design, Diffraction, Spectroscopy, Polarization, Inspection, Holography

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Proceedings Article | 12 July 2019 Open Access

Tailored dispersive elements for adapted spectrometric sensing

Torsten Diehl, Peter Triebel, Tobias Moeller, Alexandre Gatto, Dennis Lehr, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies, Felix Koch

Proceedings Volume 11180, 111801K (2019) https://doi.org/10.1117/12.2535975

KEYWORDS: Holography, Optical design, Diffraction gratings, Spectrometers, Optics manufacturing, Manufacturing, Wavefronts, Interferometers, Spectroscopy, Photoresist materials

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Proceedings Article | 15 June 2018 Paper

Optical gratings with low wavefront aberrations and low straylight for enhanced spectroscopical applications

Torsten Diehl, Peter Triebel, Tobias Moeller, Alexandre Gatto, Dennis Lehr, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies, Felix Koch

Proceedings Volume 10692, 106920H (2018) https://doi.org/10.1117/12.2313550

KEYWORDS: Holography, Spectrometers, Optical design, Optics manufacturing, Manufacturing, Optical components, Satellites, Diffraction gratings, Wavefront aberrations, Photoresist materials

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The sensing performance of spectroscopic systems can be enhanced by improving their optical core-element: the optical grating. in particular for imaging spectrometers - especially Hyper-Spectral Imagers - beside the polarization sensitivity and efficiency the imaging quality of the diffraction grating is an important parameter. Optical elements within the spectrometer are manufactured while aiming on lowest wave front aberrations. Thus, least imaging aberration quality of the grating is required not to limit the overall imaging quality of the instrument. Different types of spectrometers (Offner, Czerny Turner) lead to different requirements for the grating surface figure. Beside wavefront aberrations the straylight of gratings will impact the optical performance of spectrometers too. Both parameters are crucially influenced by the manufacturing processes. During the manufacturing process of the grating substrate, a sequence of polishing steps can be applied in order to minimize the wavefront aberrations and roughness. Chemical assisted polishing in combination with classical techniques lead to least surface roughness. A good practice for the manufacturing of aspheres and freeform substrates is the generation of an initial figure close to the final shape only by a classical process, followed by a careful applied aspherization. The imaging performance (wavefront and straylight) of the grating is also optimized due to the recording setup of the holography - including all employed optics for the wave forming. Holographically manufactured gratings with adapted wave forming functions are used for transmission or reflection gratings on different types of substrates like prisms, convex and concave spherical and aspherical surface shapes, up to free-form elements. Numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) work on the optical design principles of reflection gratings. All those manufactured gratings can be coated with adapted coatings to support their reflection or transmission operation. The present approach can be applied to manufacture high quality reflection gratings for the EUV to the IR. In this paper we report our results on designing and manufacturing high quality gratings based on holographic processes in order to enable diffraction limited complex spectrometric setups over certain wavelength ranges. Most beneficial is an optimization of the grating during spectrometer design phase while regarding the manufacturing as well. However, the initial optical design approach will show that gratings can be tailored to the specific requirements of the spectrometer (in order to enhance the imaging quality). The enhancement of the optical performance may lead to a specific wavefront shape after the grating element. this special capability for aberration reduction can be defined to the grating during the holographic process. In general, holography enables to manufacture gratings with a specific and adapted wavefront error compensation functions. Beside the results of low aberration gratings the results on straylight measurements will be presented. Recent results and optimization will be shown.

Proceedings Article | 17 November 2017 Open Access

Space applications: monolithic diffraction grating elements from EUV to NIR spectral range

Alexandre Gatto, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies, Torsten Diehl, Peter Triebel, Tobias Moeller

Proceedings Volume 10563, 1056315 (2017) https://doi.org/10.1117/12.2304153

KEYWORDS: Diffraction gratings, Manufacturing, Holography, Near infrared, Optics manufacturing, Optical design, Diffraction, Polarization, Extreme ultraviolet, Spectroscopy

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Proceedings Article | 25 September 2017 Open Access

Low aberration monolithic diffraction gratings for high performance optical spectrometers

Peter Triebel, Tobias Moeller, Torsten Diehl, Alexandre Gatto, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies

Proceedings Volume 10562, 1056207 (2017) https://doi.org/10.1117/12.2296116

KEYWORDS: Diffraction gratings, Manufacturing, Polarization, Holography, Spectrometers, Wavefront aberrations, Wavefronts, Reflection, Prisms, Optical design

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Gratings are the core element of the spectrometer. For imaging spectrometers beside the polarization sensitivity and efficiency the imaging quality of the diffraction grating is essential. Lenses and mirrors can be produced with lowest wavefront aberrations. Low aberration imaging quality of the grating is required not to limit the overall imaging quality of the instrument. Different types of spectrometers will lead to different requirements on the wavefront aberrations for their specific diffraction gratings. The wavefront aberration of an optical grating is a combination of the substrate wavefront and the grating wavefront. During the manufacturing process of the grating substrate different processes can be applied in order to minimize the wavefront aberrations. The imaging performance of the grating is also optimized due to the recording setup of the holography.

This technology of holographically manufactured gratings is used for transmission and reflection gratings on different types of substrates like prisms, convex and concave spherical and aspherical surface shapes, free-form elements. All the manufactured gratings are monolithic and can be coated with high reflection and anti-reflection coatings. Prism substrates were used to manufacture monolithic GRISM elements for the UV to IR spectral range preferably working in transmission. Besides of transmission gratings, numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) working on the optical design principles of reflection gratings. The present approach can be applied to manufacture high quality reflection gratings for the EUV to the IR.

In this paper we report our latest results on manufacturing lowest wavefront aberration gratings based on holographic processes in order to enable at least diffraction limited complex spectrometric setups over certain wavelength ranges. Beside the results of low aberration gratings the latest achievements on improving efficiency together with less polarization sensitivity of diffractive gratings will be shown for different grating profiles.

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Proceedings Article | 19 September 2017 Presentation

Imaging gratings: Technology and applications for spectrometers (Conference Presentation)

Peter Triebel, Tobias Moeller, Torsten Diehl, Alexandre Gatto, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies

Proceedings Volume 10402, 104020J (2017) https://doi.org/10.1117/12.2275131

KEYWORDS: Diffraction gratings, Manufacturing, Spectrometers, Reflection, Optical design, Wavefront aberrations, Holography, Infrared spectroscopy, Polarization, Wavefronts

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Proceedings Article | 8 October 2015 Paper

Enhanced monolithic diffraction gratings with high efficiency and reduced polarization sensitivity for remote sensing applications

Peter Triebel, Torsten Diehl, Tobias Moeller, Alexandre Gatto, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies

Proceedings Volume 9641, 96410H (2015) https://doi.org/10.1117/12.2194326

KEYWORDS: Diffraction gratings, Polarization, Manufacturing, Optical design, Binary data, Holography, Remote sensing, Spectroscopy, Prisms, Etching

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Spectral imaging systems lead to enhanced sensing properties when the sensing system provides sufficient spectral resolution to identify materials from its spectral reflectance signature. The performance of diffraction gratings provides an initial way to improve instrumental resolution. Thus, subsequent manufacturing techniques of high quality gratings are essential to significantly improve the spectral performance. The ZEISS unique technology of manufacturing real-blazed profiles and as well as lamellar profiles comprising transparent substrates is well suited for the production of transmission gratings. In order to reduce high order aberrations, aspherical and free-form surfaces can be alternatively processed to allow more degrees of freedom in the optical design of spectroscopic instruments with less optical elements and therefore size and weight advantages. Prism substrates were used to manufacture monolithic GRISM elements for UV to IR spectral range. Many years of expertise in the research and development of optical coatings enable high transmission anti-reflection coatings from the DUV to the NIR. ZEISS has developed specially adapted coating processes (Ion beam sputtering, ion-assisted deposition and so on) for maintaining the micro-structure of blazed gratings in particular. Besides of transmission gratings, numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) working on the optical design principles of reflection gratings. This technology steps can be applied to manufacture high quality reflection gratings from the EUV to the IR applications with an outstanding level of low stray light and ghost diffraction order by employing a combination of holography and reactive ion beam etching together with the in-house coating capabilities. We report on results of transmission gratings on plane and curved substrates and GRISM elements with enhanced efficiency of the grating itself combined with low scattered light in the angular distribution. Beside of the results of straylight measurement the actual results on improving efficiency and lowering the polarization sensitivity for transmission gratings will be discussed on theoretical simulations compared to measured data over the entire wavelength range.

Proceedings Article | 14 September 2015 Paper

Optical gratings and grisms: developments on straylight and polarization sensitivity improved microstructures

Torsten Diehl, Peter Triebel, Tobias Moeller, Alexandre Gatto, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies

Proceedings Volume 9611, 96110W (2015) https://doi.org/10.1117/12.2188081

KEYWORDS: Diffraction gratings, Polarization, Manufacturing, Optical design, Holography, Prisms, Etching, Reflection, Ultraviolet radiation, Spectroscopy

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Spectral imaging systems lead to enhanced sensing properties when the sensing system provides sufficient spectral resolution to identify materials from its spectral reflectance signature. The performance of diffraction gratings provides an initial way to improve instrumental resolution. Thus, subsequent manufacturing techniques of high quality gratings are essential to significantly improve the spectral performance. The ZEISS unique technology of manufacturing real-blazed profiles comprising transparent substrates is well suited for the production of transmission gratings. In order to reduce high order aberrations, aspherical and free-form surfaces can be alternatively processed to allow more degrees of freedom in the optical design of spectroscopic instruments with less optical elements and therefore size and weight advantages. Prism substrates were used to manufacture monolithic GRISM elements for UV to IR spectral range. Many years of expertise in the research and development of optical coatings enable high transmission anti-reflection coatings from the DUV to the NIR. ZEISS has developed specially adapted coating processes (Ion beam sputtering, ion-assisted deposition and so on) for maintaining the micro-structure of blazed gratings in particular. Besides of transmission gratings, numerous spectrometer setups (e.g. Offner, Rowland circle, Czerny-Turner system layout) working on the optical design principles of reflection gratings. This technology steps can be applied to manufacture high quality reflection gratings from the EUV to the IR applications with an outstanding level of low stray light and ghost diffraction order by employing a combination of holography and reactive ion beam etching together with the in-house coating capabilities. We report on results of transmission, reflection gratings on plane and curved substrates and GRISM elements with enhanced efficiency of the grating itself combined with low scattered light in the angular distribution. Focusing on the straylight characteristic a measurement of the actual straylight level, preferably with extremely high precision, was performed and will be discussed in this paper. Beside of the results of straylight measurement the actual results on improving efficiency for transmission and reflection gratings will be discussed on theoretical simulations compared to measured data over the entire wavelength range.

Proceedings Article | 7 October 2014 Paper

Monolithic diffraction grating elements for remote sensing applications

Alexandre Gatto, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexander Kalies, Torsten Diehl, Peter Triebel, Tobias Moeller

Proceedings Volume 9241, 92411J (2014) https://doi.org/10.1117/12.2067226

KEYWORDS: Diffraction gratings, Manufacturing, Holography, Polarization, Remote sensing, Diffraction, Ion beams, Optics manufacturing, Spectrometers, Imaging spectroscopy

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Proceedings Article | 23 September 2013 Paper

Fabrication of low straylight holographic gratings for space applications

Reinhard Steiner, Alexander Pesch, Lars Erdmann, Matthias Burkhardt, Alexandre Gatto, Robert Wipf, Torsten Diehl, H. J. P. Vink, B.G. van den Bosch

Proceedings Volume 8870, 88700H (2013) https://doi.org/10.1117/12.2025269

KEYWORDS: Diffraction gratings, Stray light, Holography, Diffraction, Spectrometers, Manufacturing, Optics manufacturing, Polarization, Optical testing, Optical design

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Showing 5 of 10 publications

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