Impact of segmented deformable mirrors on high-contrast testbeds for exoplanet imaging with future large space telescopes: contrast stability assessment on the HiCAT bench
Abstract
We investigate the stability of a segmented deformable mirror (DM) on high-contrast testbeds and its impact on the images produced with coronagraphs. Segmented apertures are promising to obtain large primary mirrors for future missions with starlight suppression capabilities. Cophased at the sub-nanometer level, segments can be slightly misaligned by small drifts, proving harmful for exoplanet observations. We study the impact of misalignments on contrast using the High-contrast Imager for Complex Aperture Telescopes (HiCAT), a testbed which includes a 37-segment DM and produces coronagraphic images with 2.5e-8 contrast in narrowband light. Temporal wavefront errors due to the segmented DM are estimated with a Zernike wavefront sensor. Our in-lab results show aberrations at the sub-nanometer level, proving encouraging for contrast stability studies. We then use a digital twin of HiCAT to simulate coronagraphic images with an initial 0.5e-8 contrast and the segments in flat position. By injecting known perturbations on the segments, we observe a contrast degradation by a factor of 2.5, nearly corresponding to the typical contrast observed on HiCAT. These results highlight the importance of segment cophasing sensing and control strategies to ensure the required contrasts for exo-Earth imaging with a large segmented aperture for the Habitable Worlds Observatory mission.
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BibTeX
@article{buralli2026impact,
title = {{Impact of segmented deformable mirrors on high-contrast testbeds for exoplanet imaging with future large space telescopes: contrast stability assessment on the HiCAT bench}},
author = {Benjamin Buralli and Mamadou N'Diaye and Raphaël. Pourcelot and Marcel Carbillet and Emiel H. Por and Iva Laginja and Ludovic Canas and Sarah Steiger and Peter Petrone and Meiji M. Nguyen and Bryony Nickson and Susan F. Redmond and Ananya Sahoo and Laurent Pueyo and Marshall D. Perrin and Rémi Soummer},
journal = {Journal of Astronomical Telescopes Instruments and Systems},
year = {2026},
month = may,
doi = {10.1117/1.jatis.12.2.029002},
eprint = {2604.25675},
archivePrefix = {arXiv},
url = {https://hal.science/hal-05792935v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Impact of segmented deformable mirrors on high-contrast testbeds for exoplanet imaging with future large space telescopes: contrast stability assessment on the HiCAT bench
AU - Benjamin Buralli
AU - Mamadou N'Diaye
AU - Raphaël. Pourcelot
AU - Marcel Carbillet
AU - Emiel H. Por
AU - Iva Laginja
AU - Ludovic Canas
AU - Sarah Steiger
AU - Peter Petrone
AU - Meiji M. Nguyen
AU - Bryony Nickson
AU - Susan F. Redmond
AU - Ananya Sahoo
AU - Laurent Pueyo
AU - Marshall D. Perrin
AU - Rémi Soummer
PY - 2026
DA - 2026/05/22
JO - Journal of Astronomical Telescopes Instruments and Systems
DO - 10.1117/1.jatis.12.2.029002
UR - https://hal.science/hal-05792935v1
AB - We investigate the stability of a segmented deformable mirror (DM) on high-contrast testbeds and its impact on the images produced with coronagraphs. Segmented apertures are promising to obtain large primary mirrors for future missions with starlight suppression capabilities. Cophased at the sub-nanometer level, segments can be slightly misaligned by small drifts, proving harmful for exoplanet observations. We study the impact of misalignments on contrast using the High-contrast Imager for Complex Aperture Telescopes (HiCAT), a testbed which includes a 37-segment DM and produces coronagraphic images with 2.5e-8 contrast in narrowband light. Temporal wavefront errors due to the segmented DM are estimated with a Zernike wavefront sensor. Our in-lab results show aberrations at the sub-nanometer level, proving encouraging for contrast stability studies. We then use a digital twin of HiCAT to simulate coronagraphic images with an initial 0.5e-8 contrast and the segments in flat position. By injecting known perturbations on the segments, we observe a contrast degradation by a factor of 2.5, nearly corresponding to the typical contrast observed on HiCAT. These results highlight the importance of segment cophasing sensing and control strategies to ensure the required contrasts for exo-Earth imaging with a large segmented aperture for the Habitable Worlds Observatory mission.
SN - 2329-4124
SN - 2329-4221
ER -