Optical surfaces with extreme quality – NANO-PtoV

Today, the large instruments of instrumental Physics, such as X-synchrotron, Advanced-LIGO-VIRGO detectors for the detection of gravitational waves, or the instruments of large ground and space observatories dedicated to the detection of extra-solar planets (VLT-SPHERE, ROMAN ST), already require optical components of extreme quality in terms of shape precision (of the order of a few nanometers on average) and surface quality (roughness of a few Ångström).

The next generation of X-synchrotrons or instruments planned for 2030+, such as the Einstein telescope or the LISA space interferometer, third generation gravitational wave detectors, as well as mission projects such as HabEx and LUVOIR, proposed at the 2020 NASA Decadal and dedicated to the characterization of exo-Earths, once again requires pushing back the feasibility limits in terms of precision of optical surfaces, almost of an order of magnitude.

The NANO-PtoV Joint Laboratory, proposed by the Laboratoire d'Astrophysique de Marseille (LAM, Aix-Marseille University / CNRS / CNES) and the industrialist Winlight Optics (Bertin Technology group) thus aims to simultaneously advance on the two aspects essential to the achievement of extreme optics, which are the polishing process and the associated metrology.

The developments that will be tackle within LabCom NANO-PtoV will therefore aim to:
1 / - be able to master the polishing process at the quasi-atomic level, making it possible to generate surfaces with a residual error in medium and high spatial frequencies of the order of one nanometer peak-to-valley, with roughness at the level of one Ångström
2 / - be able to measure these residual defects with ten times better precision, on dimensions that can easily reach one meter and increasingly complex parts, potentially freeform.

These two issues are very closely related, impossible to produce non-measurable optical parts, and present common challenges in terms of process control (chemistry, abrasion, interferometry, analysis, etc.) and environmental stability (PH of solutions, hygrometry, temperature, vibration, etc.).