Mr. Sylvain Egron Profile

Sylvain Egron

at ONERA

SPIE Involvement:

Author

Publications (13)

Proceedings Article | 6 October 2023 Presentation

High-contrast imager for complex aperture telescopes (HiCAT): 10. Broadband Zernike wavefront sensor under natural and artificial drifts

John Hagopian, Raphaël Pourcelot, Emiel Por, Mamadou N'Diaye, Benjamin Buralli, Marcel Carbillet, Kjetil Dohlen, Sylvain Egron, Marc Ferrari, Rachel Fox, Rob Gontrum, Iva Laginja, Meiji Nguyen, Bryony Nickson, Marshall Perrin, Peter Petrone, Laurent Pueyo, Susan Redmond, Ananya Sahoo, Anand Sivaramakrishnan, Hari Subedi, Sam Weinstock, Scott Will, Rémi Soummer

Proceedings Volume 12680, 126801F (2023) https://doi.org/10.1117/12.2677790

KEYWORDS: Wavefront sensors, Telescopes, Imaging systems, Coronagraphy, Deformable mirrors, Stars, Monochromatic aberrations, Image segmentation, Wavefront aberrations, Observatories

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Proceedings Article | 21 August 2018 Presentation + Paper

High-contrast imager for complex aperture telescopes (HiCAT): 5. first results with segmented-aperture coronagraph and wavefront control

Élodie Choquet, A. J. Eldorado Riggs, Rémi Soummer, Gregory Brady, Keira Brooks, Thomas Comeau, Tom Dillon, Sylvain Egron, Rob Gontrum, John Hagopian, Iva Laginja, Lucie Leboulleux, Marshall Perrin, Peter Petrone, Laurent Pueyo, Johan Mazoyer, Mamadou N'Diaye, Ron Shiri, Anand Sivaramakrishnan, Kathryn St. Laurent, Ana-Maria Valenzuela, Neil Zimmerman

Proceedings Volume 10698, 106981O (2018) https://doi.org/10.1117/12.2314110

KEYWORDS: Coronagraphy, Space telescopes, Wavefronts, Telescopes, Metrology, Phase retrieval, Carbon nanotubes

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Segmented telescopes are a possible approach to enable large-aperture space telescopes for the direct imaging and spectroscopy of habitable worlds. However, the increased complexity of their aperture geometry, due to the central obstruction, support structures and segment gaps, makes high-contrast imaging very challenging. The High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed was designed to study and develop solutions for such telescope pupils using wavefront control and coronagraphic starlight suppression. The testbed design has the flexibility to enable studies with increasing complexity for telescope aperture geometries starting with off-axis telescopes, then on-axis telescopes with central obstruction and support structures - e.g. the Wide Field Infrared Survey Telescope (WFIRST) - up to on-axis segmented telescopes, including various concepts for a Large UV, Optical, IR telescope (LUVOIR). In the past year, HiCAT has made significant hardware and software updates in order to accelerate the development of the project. In addition to completely overhauling the software that runs the testbed, we have completed several hardware upgrades, including the second and third deformable mirror, and the first custom Apodized Pupil Lyot Coronagraph (APLC) optimized for the HiCAT aperture, which is similar to one of the possible geometries considered for LUVOIR. The testbed also includes several external metrology features for rapid replacement of parts, and in particular the ability to test multiple apodizers readily, an active tip-tilt control system to compensate for local vibration and air turbulence in the enclosure. On the software and operations side, the software infrastructure enables 24/7 automated experiments that include routine calibration tasks and high-contrast experiments. In this communication we present an overview and status update of the project, both on the hardware and software side, and describe the results obtained with APLC wavefront control.

Proceedings Article | 21 August 2018 Paper

James Webb Space Telescope optical simulation testbed V: wide-field phase retrieval assessment

Sylvain Egron, Mamadou N'Diaye, Iva Laginja, Greg Brady, Rémi Soummer, Charles-Philippe Lajoie, Aurélie Bonnefois, Vincent Michau, Élodie Choquet, Marc Ferrari, Lucie Leboulleux, Olivier Levecq, Marshall Perrin, Peter Petrone, Laurent Pueyo, Anand Sivaramakrishnan, Christopher Moriarty

Proceedings Volume 10698, 106983N (2018) https://doi.org/10.1117/12.2313892

KEYWORDS: Wavefronts, James Webb Space Telescope, Monochromatic aberrations, Point spread functions, Wavefront sensors, Mirrors, Cameras, Space telescopes, Telescopes, Phase retrieval

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Proceedings Article | 25 September 2017 Open Access

James Webb Space telescope optical simulation testbed: experimental results with linear control alignment

Charles-Philippe Lajoie, Aurélie Bonnefois, Lucie Leboulleux, Laurent Pueyo, Marie Ygouf, Rémi Soummer, Sylvain Egron, Vincent Michau, Clément Escolle, Mamadou N'Diaye, Elodie Choquet, Marshall Perrin, Thierry Fusco, Marc Ferrari, Emmanuel Hugot

Proceedings Volume 10562, 1056225 (2017) https://doi.org/10.1117/12.2296105

KEYWORDS: James Webb Space Telescope, Wavefronts, Space telescopes, Optical alignment, Optical simulations, Mirrors, Optical testing, Telescopes, Wavefront sensors, Astronomical imaging

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Proceedings Article | 25 September 2017 Open Access

Comparison of wavefront control algorithms and first results on the high-contrast imager for complex aperture telescopes (hicat) testbed

L. Leboulleux, S. Egron, M. N'Diaye, J. Mazoyer, L. Pueyo, M. Perrin, J.-F. Sauvage, E. Choquet, T. Fusco, R. Soummer

Proceedings Volume 10562, 105622Z (2017) https://doi.org/10.1117/12.2296154

KEYWORDS: Wavefronts, Coronagraphy, Space telescopes, Speckle, Telescopes, Deformable mirrors, Calibration, Wavefront sensors, Actuators, Imaging systems

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Proceedings Article | 5 September 2017 Paper

James Webb Space Telescope optical simulation testbed IV: linear control alignment of the primary segmented mirror

Sylvain Egron, Rémi Soummer, Vincent Michau, Aurélie Bonnefois, Marc Ferrari, Marshall Perrin, Laurent Pueyo, Mamadou N'Diaye, Charles-Philippe Lajoie, Joseph Long, Elodie Choquet, Olivier Levecq, Johan Mazoyer, Peter Petrone, Lucie Leboulleux, Anand Sivaramakrishnan

Proceedings Volume 10398, 1039811 (2017) https://doi.org/10.1117/12.2272981

KEYWORDS: Wavefronts, James Webb Space Telescope, Segmented mirrors, Wavefront sensors, Space telescopes, Optical alignment, Mirrors, Optical simulations, Optical testing, Telescopes

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Proceedings Article | 1 September 2017 Presentation + Paper

Capabilities of ACAD-OSM, an active method for the correction of aperture discontinuities

Mamadou N'Diaye, Kevin Fogarty, Colin Norman, Lucie Leboulleux, Sylvain Egron, Johan Mazoyer, Laurent Pueyo

Proceedings Volume 10400, 104000G (2017) https://doi.org/10.1117/12.2273070

KEYWORDS: Deformable mirrors, Exoplanets, Imaging systems, Coronagraphy, Active optics, Actuators, Wavefronts, Control systems, Interferometry, Adaptive optics

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Proceedings Article | 9 August 2016 Paper

Wide-field corrector for 4MOST: design details and MAIV processes

Nicolas Azais, Greg Smith, Samuel Barden, Bernard Delabre, Damien Jones, Sylvain Egron

Proceedings Volume 9908, 990889 (2016) https://doi.org/10.1117/12.2232304

KEYWORDS: Telescopes, Cameras, Manufacturing, Optics manufacturing, Glasses, Lenses, Coating, Mirrors, Optical components, Image quality

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Proceedings Article | 29 July 2016 Paper

High-contrast imager for Complex Aperture Telescopes (HiCAT). 4. Status and wavefront control development

Lucie Leboulleux, A. J. Riggs, Sylvain Egron, Laurent Pueyo, Elodie Choquet, Marshall Perrin, Jean-François Sauvage, Thierry Fusco, Rémi Soummer, Jeremy Kasdin, Mamadou N'Diaye, Johan Mazoyer

Proceedings Volume 9904, 99043C (2016) https://doi.org/10.1117/12.2233640

KEYWORDS: Space telescopes, Telescopes, Wavefronts, Coronagraphy, Speckle, Point spread functions, Mirrors, Cameras, Infrared telescopes, Ultraviolet telescopes

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Segmented telescopes are a possible approach to enable large-aperture space telescopes for the direct imaging and spectroscopy of habitable worlds. However, the increased complexity of their aperture geometry, due to their central obstruction, support structures and segment gaps, makes high-contrast imaging very challenging. The High-contrast imager for Complex Aperture Telescopes (HiCAT) was designed to study and develop solutions for such telescope pupils using wavefront control and starlight suppression. The testbed design has the flexibility to enable studies with increasing complexity for telescope aperture geometries starting with off-axis telescopes, then on-axis telescopes with central obstruction and support structures (e.g. the Wide Field Infrared Survey Telescope [WFIRST]), up to on-axis segmented telescopes e.g. including various concepts for a Large UV, Optical, IR telescope (LUVOIR), such as the High Definition Space Telescope (HDST). We completed optical alignment in the summer of 2014 and a first deformable mirror was successfully integrated in the testbed, with a total wavefront error of 13nm RMS over a 18mm diameter circular pupil in open loop. HiCAT will also be provided with a segmented mirror conjugated with a shaped pupil representing the HDST configuration, to directly study wavefront control in the presence of segment gaps, central obstruction and spider. We recently applied a focal plane wavefront control method combined with a classical Lyot coronagraph on HiCAT, and we found limitations on contrast performance due to vibration effect. In this communication, we analyze this instability and study its impact on the performance of wavefront control algorithms. We present our Speckle Nulling code to control and correct for wavefront errors both in simulation mode and on testbed mode. This routine is first tested in simulation mode without instability to validate our code. We then add simulated vibrations to study the degradation of contrast performance in the presence of these effects.

Proceedings Article | 29 July 2016 Paper

James Webb Space Telescope optical simulation testbed III: first experimental results with linear-control alignment

Sylvain Egron, Marshall Perrin, Élodie Choquet, Lucie Leboulleux, Laurent Pueyo, Vincent Michau, Clément Escolle, Marc Ferrari, Aurélie Bonnefois, Rémi Soummer, Mamadou N'Diaye, Charles-Philippe Lajoie, Marie Ygouf, Thierry Fusco, Emmanuel Hugot

Proceedings Volume 9904, 99044A (2016) https://doi.org/10.1117/12.2233650

KEYWORDS: James Webb Space Telescope, Wavefront sensors, Space telescopes, Mirrors, Optical simulations, Wavefronts, Telescopes, Optical alignment, Cameras, Zemax

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Proceedings Article | 11 September 2015 Paper

High-contrast imager for complex aperture telescopes (HiCAT): 3. first lab results with wavefront control

Mamadou N'Diaye, Élodie Choquet, Johan Mazoyer, Alexis Carlotti, Laurent Pueyo, Sylvain Egron, Lucie Leboulleux, Olivier Levecq, Marshall Perrin, Chris Long, Rachel Lajoie, Rémi Soummer

Proceedings Volume 9605, 96050I (2015) https://doi.org/10.1117/12.2188497

KEYWORDS: Coronagraphy, Wavefronts, Telescopes, Image segmentation, Actuators, Speckle, Humidity, Space telescopes, Mirrors, Imaging systems

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Proceedings Article | 28 August 2014 Paper

High-contrast Imager for Complex Aperture Telescopes (HICAT): II. Design overview and first light results

Mamadou N'Diaye, Elodie Choquet, Laurent Pueyo, Erin Elliot, Marshall Perrin, J. Kent Wallace, Rachel Anderson, Olivier Levecq, Chris Long, Rémi Soummer, Sylvain Egron, Lucie Leboulleux, Audrey DiFelice, Emmanuel Hugot, Michel Marcos, Marc Ferrari

Proceedings Volume 9143, 914327 (2014) https://doi.org/10.1117/12.2056694

KEYWORDS: Optics manufacturing, Optical alignment, Coronagraphy, Mirrors, Wavefronts, Telescopes, Space telescopes, Wavefront sensors, Cameras, Imaging systems

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Proceedings Article | 2 August 2014 Paper

James Webb Space Telescope Optical Simulation Testbed I: overview and first results

Marshall Perrin, Rémi Soummer, Olivier Levecq, Mamadou N'Diaye, Élodie Choquet, Charles-Philippe Lajoie, Laurent Pueyo, Erin Elliott, Rachel Anderson, George Hartig, Chris Long, Marie Ygouf, Lucie Leboulleux, Sylvain Egron, Roeland van der Marel, Matt Mountain

Proceedings Volume 9143, 914309 (2014) https://doi.org/10.1117/12.2056936

KEYWORDS: James Webb Space Telescope, Mirrors, Image segmentation, Wavefront sensors, Telescopes, Phase retrieval, Adaptive optics, Optical alignment, Space telescopes, Sensors

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Showing 5 of 13 publications

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