Experimentos práticos para sistemas de óptica adaptativa laser em telescópios gigantes

Abstract

Laser guide stars are used in adaptive optics to simulate a reference point in the sky, essential for correcting atmospheric distortions. However, they can suffer from significant deformations (elongation/truncation), hindering accurate wavefront measurements. While the theoretical study by (PIRES et al., 2024) showed promising results in simulations, experimental validation under real conditions was still lacking. This work addresses that gap by testing, on an adaptive optics (AO) bench, a robust centroiding method resilient to such deformations, aiming to improve wavefront sensors. The Maximum Likelihood (ML) method, implemented in MATLAB, estimates the ideal centroid position based on the sodium layer profile and Poisson noise. Results, compared to geometric reference centers, showed good accuracy and convergence under varying deformation conditions. During testing, environmental noise from the AO bench required adaptations, such as replacing the laser with optical masks. An unwanted peripheral effect in centroid detection—caused by Poisson noise sensitivity—was mitigated using thresholding techniques. Despite some limitations, the ML method proved applicable in noisy environments, pointing to promising developments for large telescopes and new correction strategies in adaptive optics.