arXiv subjects

Elisabetta Cesarini

Publications and source records attributed to Elisabetta Cesarini.

2 recordsLinked to original sources

arXiv2026

High-Stability Deformable Mirrors for Correcting Non-Axisymmetric Residual Aberrations in Thermal Compensation of Future Gravitational Wave Interferometers

In gravitational wave detectors, optical aberrations arise mainly from laser absorption in coatings and production process defects in the optics along the laser path. If left uncorrected, these optical path distortions drive the interferometer away from its optimal working point, degrading both stability and sensitivity. Future instruments such as the Einstein Telescope high-frequency detector will operate with unprecedented circulating power, further amplifying the aberration budget. In the current detectors Advanced Virgo and Advanced LIGO, the axisymmetric distortions are corrected using thermal actuators and CO2 laser projectors, however, non-axisymmetric wavefront distortions remain unmitigated. Deformable mirrors are investigated as a flexible solution for mitigating such defects: by shaping the CO2 beam phase upon reflection, they can imprint the required asymmetric intensity pattern on the lensing optics without introducing frequency dependent noise. The target phase map is computed via a modified Gerchberg-Saxton algorithm. We present simulations of this projection strategy and experimental validation demonstrating consistent reproduction of the desired intensity patterns.

gr-qc↗

arXiv2022

A Systematic Error in the Internal Friction Measurement of Coatings for Gravitational Waves Detectors

Low internal friction coatings are key components of advanced technologies such as optical atomic clocks and high-finesse optical cavity and often lie at the forefront of the most advanced experiments in Physics. Notably, increasing the sensitivity of gravitational-wave detectors depends in a very large part on developing new coatings, which entails developing more suitable methods and models to investigate their loss angle. In fact, the most sensitive region of the detection band in such detectors is limited by the coating thermal noise, which is related to the loss angle of the coating. Until now, models which describe only ideal physical properties have been adopted, wondering about the use of one or more loss angles to describe the mechanical properties of coatings. Here we show the presence of a systematic error ascribed to inhomogeneity of the sample at its edges in measuring the coating loss angle. We present a model for disk-shaped resonators, largely used in loss angle measurements, and we compare the theory with measurements showing how this systematic error impacts on the accuracy with which the loss model parameters are known.

astro-ph.IM↗