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Description
Enhancing the sensitivity of gravitational-wave detectors represents a major challenge as it requires stable operation at progressively higher optical powers. Increased circulating power within the Fabry–Pérot arm cavities amplifies thermal effects, leading to wavefront aberrations that, if not properly compensated, can significantly degrade the instrument’s performance.
For the foreseen O5 Advanced Virgo upgrade, the circulating power in the interferometer arms is expected to reach several hundreds of kilowatts, making the Thermal Compensation System a crucial feature of the project. In view of the relevant modifications of interferometer’s optical layout — such as the installation of stable recycling cavities — an extensive study of the TCS actuation strategy in this new configuration is underway. Thermal and structural simulations are being carried out to investigate the effects induced in this high-power regime and to define optimal compensation strategies to ensure the interferometer performance.
We present the outcomes of optical and structural simulation studies in the O5 configuration with stable cavities, with particular emphasis on residual optical path length (OPL) affecting ITF’s figures of merit and the impact of the spatial frequency content of aberrations.