Speaker
Description
High power cavity systems require sophisticated thermal compensation systems to maintain resonant fields while the mirrors experience significant thermal actuation. The efficacy of these systems is limited by the ability to understand and model these effects. aLIGO's thermal model has previously been unable to accurately predict the thermal state, impeding the improvement of these systems and reaching the desired 550MW in O5. Improving these models is not trivial as a full interferometer model is sensitive to the position and curvatures of every optic, creating an enormous parameter space which is difficult to experimentally verify due to long time constants and inaccessible vacuum optics.
We have implemented a nested sampling model comparing finesse and mismatch measurements between a single pass through the interferometer with the output mode cleaner cavity mode to explore this large parameter space. By using states where the actuators are deforming individual mirrors, we can break the degeneracy between their position and radius of curvature. This presentation will discuss the inferred positions and radius of curvature for optics in the power and signal recycling cavities, the resulting improvement in the detector model, and how this will assist progress towards enabling high power operation.