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# LISA AIVT Optical Ground Support Equipment technology developments

Jean-Pierre Baronick, Fabio Cortavarria, Stéphane Dheilly, Hubert Halloin, Corinne Juffroy, Matthieu Laporte, Jean Lesrel, Guy Monier, Pierre Prat, Aymeric van De Walle, et al.

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To cite this version:

Jean-Pierre Baronick, Fabio Cortavarria, Stéphane Dheilly, Hubert Halloin, Corinne Juffroy, et al. LISA AIVT Optical Ground Support Equipment technology developments. Gravitational-Wave Advanced Detector Workshop, May 2023, La Biodola (Isola d'Elba), Italy. 2023. hal-04161565

HAL Id: hal-04161565

https://hal.science/hal-04161565

Submitted on 13 Jul 2023

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# LISA AIVT Optical Ground Support Equipment technology developments

## The LISA France collaboration

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INSTITUT
FRESNEL

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L2T

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LMA

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LABORATOIRE
MATÉRIAUX
AVANÇÉS

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SYRTE

Systèmes de Référence Temps-Espace

## Context

* LISA based on heterodyne laser interferometry -> measure tiny change distance between free-falling mirrors

* LISA strain sensitivity: $1 \cdot 10^{-20} / \sqrt{Hz}$

* LISA displacement sensitivity: $10 \cdot 10^{-12} m / \sqrt{Hz}$ over $2.5 \cdot 10^9 m$

* France is in charge of the Interferometric Detection System (IDS) tests and Optical Test System (OTS)

* Specific test equipments to verify the requirements

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## MIFO: Metallic InterFerOmeter

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global performances of the MIFO, in a reference configuration, under vacuum with a heterodyne frequency of $15 \text{ MHz} + 15 \text{ Hz}$

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* Develop ultra-stable laser and injectors

* Update a dedicated phasemeter

* Setting-up test infrastructures (vacuum, environment, etc)

* Identify the noise sources

* Prepare the functional tests of the subsystems for the ZIFO

## ZIFO: Zerodur InterFerOmeter

Dimensions: 530 x 450 x 47 mm

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* Develop a demonstration bench

* Determine the excess level of metrology stability -> objective $5-10 \text{ pm} / \sqrt{Hz}$ in the band $1-10 \text{ mHz}$

* Evaluate the performance limits achievable with the optical contacting

* 3 interferometers:

* 1 with equal arms

* 2 with unequal arms

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Optical simulations: Optocad, Zemax®

## TTL-OB: Tilt-To-Length measurements

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TTL measurements over 100 hours, with a stability of +/- 0.2µm

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* FF-OGSE shall measure TTL coupling -> develop a bench to demonstrate the feasibility

* Accuracy of the measurement: <0.77µm/rad

* Deliver Rx (flat-top) and REF beams, receive Tx beam

* Heterodyne detection scheme

## SLOGSE: Stray light measurements

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* Tests have been made with

- the accuracy

- the resolution in $\Delta L$ (below)

* Seems OK for $\Delta L$ measurements with precision 1mm on distances

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* Phase-locked frequency-scanned laser source

* 2 nm span, over 100 s: 5 GHz/s scan

* Detection noise floor <10<sup>-12</sup> in fract. stray light power, degrades at $\Delta L/2 < 25 \text{cm}$

* Work under way to eliminate power modulations due to the set up's fibered components

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## Conclusions & prospects

* France is in charge of the IDS tests and OTS

* Several OGSEs are needed to test the IDS and the MOSA

* First prototypes are under development to test:

* The sub-systems as laser, injectors, phasemeters, control/command

* Assess the limits on sensitivity of the set-up and the precision of the path length measurements achievable on ground

* Identify the noise sources

* Measure the TTL coupling

* Measure the straylight at system level, component by component

* Further investigation are ongoing to validate all the objectives

* Preparation of the final OGSE are in progress

## Contributors

* **APC:** J-P. Baronick, F. Cortavarria, S. Dheilly, H. Halloin, C. Juffroy, M. Laporte, J. Lesrel, G. Monier, P. Prat, A. Van De Walle, M. Vincent, T. Zerguerras

* **ARTEMIS:** S. Bruhier, F. Cleva, J-P. Coulon, N. Dinu-Jaeger, T. Friess, D. Huet, B. Lefevre, M. Lintz, M. Merzougui, M. Nardello, M. Pichot, A. Pouzolles, A. Roubeau-Tissot, I. Thiellement, J-Y. Vinet

* **CEA:** N. Arab, A. Arhancet, D. Bachet, M. Besançon, N. Besson, R. Granelli, M. Lacroix, A. Petiteau, C. Pitte, S. Sube

* **CNES:** R. Arguel, E. Courau, J-C. Damery, F-X. Esnault, O. Grosjean, R. Llorca-Cejudo, E. Rivière

* **CPPM:** M. Dupont, L. Guevara, E. Kajfasz, O. Llido, Ch. Meessen, A. Rivière, J. Royon, A. Secroun, J. Zoubian

* **L2IT:** C. Buy

* **LAM:** M. Carle, C. Fabron, B. Foulon, J.L. Gimenez

* **SYRTE:** O. Acef, A. Mehlman, P. Wolf

**Funding:** CNES, CNRS/INSIS, OCA, Région Sud, UCA