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arXiv · 2608.29370

Characterization of the stabilized nulling interferometry testbed PERS\'EE

Julien Lozi
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Abstract

Observing exoplanets is hindered by high stellar contrast and tiny angular separation. Nulling interferometry addresses this by recombining two pupils for destructive interference on the star and constructive interference on the planet. However, maintaining deep nulls despite external disturbances requires sub-nanometer optical path difference (OPD) stability and sub-hundredth Airy disk pointing control. To validate this technology for a space mission, the PERSEE laboratory demonstrator bench was developed by a CNES-led consortium and integrated at the Meudon Observatory. Simulating a complete space mission setup, PERSEE targeted a stable star extinction rate of 1e-4 with variations of 1e-5 over several hours under simulated disturbances. The thesis focused on the multi-stage integration, calibration, and characterization of the bench's critical components and cophasing control loops. By implementing a Linear Quadratic Gaussian (LQG) controller optimized through preliminary disturbance measurements, the system mitigated multi-frequency vibrations (1-100 Hz, tens of nanometers amplitude), reducing residual OPD to 0.3 nm RMS and tip-tilt errors to 0.4 percent of the Airy disk. These stabilization controls achieved a record null rate of 8.8e-6 with 9e-7 stability over several hours in the 1.65-2.45um spectral band, surpassing initial specifications by an order of magnitude. Extrapolating these results to space missions indicates that with 40 cm telescopes and 100 Hz control loops, exoplanet observations are feasible for stars brighter than 9th magnitude.

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Julien Lozi. 2026-08-29. Characterization of the stabilized nulling interferometry testbed PERS\'EE. https://arxiv.org/abs/2608.29370

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