Tiny Particles, Big Noise: Stray Light Noise from Particulates Contamination in the Virgo and Einstein Telescope Gravitational-Waves Detectors

by Dr Andrea Moscatello (DFA)

Thursday 3 Jul 2025, 17:00 → 17:15 Europe/Rome

1/1-3 - Aula B (Dipartimento di Fisica e Astronomia - Edificio Marzolo)

Gravitational-wave detectors like Virgo and the future Einstein Telescope (ET) are among the most sensitive instruments ever constructed, requiring extreme cleanliness and optical precision to achieve their target sensitivity. Gravitational waves—ripples in spacetime predicted by General Relativity —were first directly detected in 2015, opening a new window onto the universe and enabling the study of phenomena such as black hole mergers and neutron star collisions.

 

An emerging concern in these detectors is the impact of dust particles, which can scatter laser light and generate stray light that couples back into the main beam, introducing excess noise—especially in the low to mid frequency range.

 

To address this, ongoing efforts focus on monitoring environmental cleanliness in interferometer facilities, particularly through high-resolution imaging of contamination on witness samples. Automated imaging and focus correction techniques are being developed to improve the accuracy and efficiency of dust quantification.

 

For the Einstein Telescope, the goal is to establish rigorous cleanliness standards during construction and operation. Studies are underway to evaluate the maximum tolerable stray light from dust, supported by analytical modeling and experimental validation. These activities aim to ensure that dust-related effects remain well below the noise budget in current and future gravitational-wave observatories.