Speaker
Description
Optimal operation of a gravitational wave (GW) detector requires clean and stable control signals. However, these signals can be compromised by various noises and optical imperfections, such as mirror surface defects or thermal aberrations which can cause the coupling of the fundamental Gaussian mode into higher-order modes. To mitigate such coupling in current detectors, sensors and thermal actuators have been installed, including phase cameras, which measure both intensity and phase of carrier and sideband beams in high resolution. However, currently in Virgo, only a fraction of the intensity information is used in the daily operation, as it is not yet understood how to interpret the remaining data.
In this work, we aim to bridge this gap through simulations. We model a three-mirror coupled cavity and analyze the output through a mode-decomposition algorithm. By characterizing how perturbations of optical parameters influence higher-order mode content, we derive sensing and actuation matrices capable of restoring the system to its optimal operating point. Following this modeling efforts, the method will be validated on a table-top setup in Nikhef, allowing us to test it with real phase camera measurements. Subsequently, it could be integrated into a full gravitational detector, targeting real-time active corrections.