Setup and performance of focal-plane characterization benches for high-precision astrometry

Detecting Earth-like exoplanets requires micro-arcsecond astrometry, which relies on a precisely calibrated focal plane equipped with high-resolution detectors. Accurate calibration depends on characterizing detector imperfections and systematic effects. Optical benches have been developed to assess the sensor’s behavior: an integrating-sphere setup for electro-optical parameters, an interferometric bench for pixel-level geometry, and a star-field projection system for intrinsic distortion. This work presents the characterization benches built for a 46-MP imaging sensor, based on the same technology as the four 220-MP detectors foreseen for the final focal-plane, and the performance metrics obtained from these setups in the context of NASA’s HWO and ESA’s M-class missions. Upgrades will bring the test environment closer to operational conditions: a second 46-MP sensor will be added for multi-detector tests, plus an adjustable-angle fringe-projection system and improved alignment.