LISA-Gravitational Wave Observatory: noise from diffused light
Laboratoire AstroParticule & Cosmologie (APC)
The LISA mission opens a whole new window into the heart of the most energetic processes in the Universe, with fundamental consequences for physics and astronomy. During its five years duration, LISA is expected to detect gravitational waves from the inspired and merger of massive black holes in the centers of galaxies or stellar clusters located at cosmological distances.
LISA is based on laser interferometry technique, and its three satellites form a giant Michelson interferometer. Scattered light by the optics, the mechanics, interaction with tubes, is an important source of noise in such antennas. The purpose of our study at APC is to evaluate the impact of scattered light from the telescope optics of the space project LISA (Laser Interferometer Space Antenna) on the detection signal of gravitationnal waves. It is important to know the intensity of scattered light (generally called « straylight ») to evaluate the sensitivity of the detector which can be compromised if the signal is muffled by noise from straylight.
This study consists in simulating with the optical design software FRED, by using real optical data measured by LMA lab, current optical properties specifications (microroughness), and by taking into account dust contamination in cleanroom. Results from simulations give intensity of scattered light when compared to the theoretical, intensity threshold calculated by INRIM.
This research will have a direct impact on the final design of LISA telescopes.
Catherine Nguyen is a research engineer at AstroParticule et Cosmologie Laboratory, in Paris. She is working as an optical engineer on ITT Telescope (Invitation to Tender) for the space mission LISA, for almost one year. The ITT Telescope is a call mission from ESA, supervised by Thales Alenia Space and with the collaboration of INRIM, SENER and other French laboratories (LMA, OCA). Her work on this project consisted of optical simulations to estimate the fraction of back-scattered light from LISA telescopes.
She graduated from Institut d’Optique Graduate School (IOGS) which is part of Université Paris-Saclay, on November 2016. IOGS is an engineering school specialized in optics and photonics, with researchers as professors from Charles Fabry laboratory. In Palaiseau (Paris), the major activities are fundamental physics, photonics, optical design and electronics. She took the speciality in Image and Signal Processing and did her last internship at General Electric Healthcare (Buc, Paris), as engineer in Image Quality team in Mammography department.