Active optics bench for the co-alignment of LSTM VIS & NIR focal planes

Anouck Paoletti; Jérémie Dain; Claude Coatantiec; Paul Jougla; Marie Laslandes

doi:10.1117/12.3022052

17 June 2024 Active optics bench for the co-alignment of LSTM VIS & NIR focal planes

Anouck Paoletti, Jérémie Dain, Claude Coatantiec, Paul Jougla, Marie Laslandes

Proceedings Volume 13019, Optical Design and Engineering IX; 1301913 (2024) https://doi.org/10.1117/12.3022052
Event: SPIE Optical Systems Design, 2024, Strasbourg, France

Abstract

The Copernicus Land Surface Temperature Monitoring, LSTM, mission will perform spatial high temporal observations of land-surface in visible, near-infrared and thermal infrared bands. LSTM payload includes a telescope feeding two optical paths: one for a visible imager (VIS) and a near-infrared imager (NIR), the other path for a thermal infrared imager (TIR). The VIS and NIR imagers contain specific freeform field lenses and shall be co-aligned with a drastic accuracy (typically +/- 5 μm). Since this co-alignment is performed before telescope availability, an on-ground testing bench (OGSE) is required to co-align VIS&NIR focal planes. This bench shall be able to emulate, field by field, the MTF performances of the LSTM telescope. OGSE main components are a spherical mirror, several beamsplitters, a deformable mirror and a wavefront sensor (WFS). The OGSE goal is to generate in closed loop representative wavefronts in VIS&NIR LSTM aperture stop plane. The particularity of this OGSE is that the output wavefront is far from being spherical since each VIS&NIR imagers field lens corrects a large WFE generated at LSTM telescope level. Furthermore, the wavefront changes significantly from one point of the field of view to another. Finally, and importantly, the OGSE needs to allow co-focussing of VNIR & SWIR detectors despite it does not illuminate both fields simultaneously. In order to simulate the OGSE achievable performances we simulate the deformable mirror on the optical design software (CodeV) with its active actuators as variable parameters.

Conference Presentation

(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.

Citation Download Citation

Anouck Paoletti, Jérémie Dain, Claude Coatantiec, Paul Jougla, and Marie Laslandes "Active optics bench for the co-alignment of LSTM VIS & NIR focal planes", Proc. SPIE 13019, Optical Design and Engineering IX, 1301913 (17 June 2024); https://doi.org/10.1117/12.3022052

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