GDR Ondes Gravitationnelles: workshop "développement des détecteurs"

mercredi 7 oct. 2026, 09:00 → 17:30 Europe/Paris

Salle tête d'or (IP2I)

Le groupe de travail "développement des détecteurs" du GdR "Ondes Gravitationnelles" organise un workshop la journée du mercredi 7 octobre 2026 à l'Institut de physique des 2 infinis de Lyon qui se déroulera de 10h à 17h. Le but de ce workshop est d'identifier et faire découvrir un large panel des activités R&D autour de la détection des ondes gravitationnelles. 

La matinée sera consacrée à la problématique de la chasse aux bruits tandis que l'après-midi permettra des discussions plus larges sur les activités de R&D dans les différentes collaborations au travers de présentations des participants.

Salle Tête d’Or, IP2I 2nd floor

Lien Zoom pour le matin: https://us02web.zoom.us/j/88574286536?pwd=3JSfu3eqItgS5MeQ6n98XlXVkJq4qx.1

Lien Zoom pour l'après-midi: https://us02web.zoom.us/j/85219641528?pwd=SaR71TZdo0UGOK2FTdXle3PUQDcY9q.1

 

09:00 → 09:45 Visite LMA

Orateur: Jerome DEGALLAIX (LMA - IP2I)

09:45 → 12:30 Noise hunting in GW detectors

09:50 Noise hunting in Virgo

Orateur: Michal Was (LAPP)

GDROG_2026-10_noiseBudget.pdf

10:30 Coffee Break

11:00 Noise hunting in LISA

Orateur: joseph Martino (APC)

Noise Hunting LISA Pathfinder Lesson Learnt_PDF.pdf

11:45 Noise hunting in MIGA

Orateur: Benjamin Canuel (LP2N CNRS/IOGS/Université de Bordeaux)

Canuel_07102026 .pdf

12:30 → 14:00 Lunch

14:00 → 17:30 Contributed talks

14:00 LISA End-To-End Test performances

Le futur détecteur d’ondes gravitationnelles, LISA (Laser Interferometer Space Antenna), est une constellation de trois satellites distants de 2.5 Mkm. Il sera le premier observatoire spatial permettant la détection d’ondes gravitationnelles de basse fréquence, dans la bande du millihertz (0.1 mHz - 1 Hz).
Dans ce contexte, il est indispensable de mener des campagnes de validation au sol à grande échelle afin de démontrer que le système métrologique optique (OMS) répond aux exigences de performance avant sa qualification en vol. Les campagnes d’essais E2ET (End-To-End Tests) coordonnées par le CNES constituent une étape cruciale de ce processus de validation, garantissant une compréhension quantitative des mécanismes de couplage du bruit, des stratégies d’étalonnage et des marges de performance avant le déploiement de la mission.
Il s’avère donc nécessaire de définir les traitements à réaliser pour vérifier chaque exigence de performance, d’identifier les niveaux de données de tests, de déterminer le plan de développement de ces traitements.
Nous présenterons le système métrologique optique testé au sol, les objectifs de performances et les challenges en terme d’analyse de données.

Orateur: Christelle Buy (L2I Toulouse, CNRS/IN2P3, Université de Toulouse)

14:20 Cryogenic loss angle of ion-beam sputtered, non-stoichiometric silicon nitride thin films

Silicon nitride (SiNx) is a highly versatile coating material. In high-reflection Bragg mirrors, it could be paired either with silica as high-index layer, for operation at any wavelength in the near infrared [1], or with amorphous silicon as low-index layer, for operation at a wavelength of 1550 nm or larger [2]; it could be used at ambient temperature as well as at cryogenic temperatures [3]. The LIGO and Virgo Collaborations have thus been studying SiNx thin films for more than a decade, using samples grown through a wide variety of deposition techniques. Thanks to this extensive research work, the optical and mechanical properties of chemical-vapor deposited SiNx are now well known, both at ambient and cryogenic temperatures [3].

In contrast, despite ion-beam sputtering (IBS) being the reference deposition technique for coating the mirrors of gravitational-wave detectors [4], to the best of our knowledge the low-temperature loss angle of IBS SiNx has never been characterized so far.

In this talk we will present the results of cryogenic loss angle measurements of as-deposited and thermally-treated IBS SiNx thin films of the best optical quality achieved so far [1], and discuss them in light of their possible use in present and future detectors such as KAGRA and Einstein Telescope.

1. A. Amato et al., Phys. Rev. D 111, 042003 (2025).
2. J. Steinlechner et al., Phys. Rev. Lett. 120, 263602 (2018).
3. M. Granata, G2502437 / VIR-1117A-25 (2025).
4. M. Granata et al., Class. Quantum Grav. 37, 095004 (2020).

Orateur: Dr M. GRANATA (CNRS)

261007_Granata_SiNx.pdf

14:40 Laser power stabilization and bright squeezing generation via radiation pressure

We will present a comparison between different schemes on bright squeezing generation. The schemes are based on the sensing of the quantum power fluctuations via the radiation-pressure motion induced on a suspended mirror by the power fluctuations and actively correcting them. We will show the fundamental limitations of these schemes, along with their capability to achieve ultra low power noise. Finally we present a realistic experimental setup based on the most promising scheme; it could generate 18dB of 10W of bright squeezing around 10Hz.

Orateur: Victor Munoz (Artemis - OCA, CNRS)

GDR-real.pptx

15:00 Characterization of Scattering Losses in the spare Output Mode Cleaner at LAPP

In this talk, we present the loss characterization of the spare OMC at LAPP. We measured the OMC's internal losses and found them to be approximately 3.4% ± 0.1%, significantly higher than the expected value of around 1.4% ± 0.4%.

To investigate the origin of these excess losses, we examined two possible scattering-related contributions. The first is surface scattering, which generates a counter-propagating beam inside the cavity and can lead to backscattering towards the interferometer, as well as additional losses of the resonant TEM00 mode. We characterize this backscattered light and evaluate its contribution to the OMC losses. The second contribution is Rayleigh scattering in the fused silica substrate.

These measurements provide insight into the origin of the excess losses observed in the OMC.

Orateur: Ward AMAR

GdR_DetectorWorkshop_Low-Loss Cavities for Advanced Virgo+.pptx

15:45 Pause