Fine tip/tilt estimation and vibration suppression for high performance AO systems

Adaptive Optics is a technique that uses the measurements of a wave front sensor to flatten distorted wave fronts with a deformable mirror in a feedback loop in order to provide diffraction limited performance with ground-based telescopes. In order to achieve the highest possible Strehl, a measure of performance, the measurement and the control of the most important atmospheric modes (tip and tilt) have to be optimized. These modes, in spite of being the first modes to be controlled, have the biggest impact on the final performance of the system. Their origin is not just atmospheric, but they originate also inside the telescope in form of vibrations due to electrical components, system eigenmodes, windshaking.