Speaker
Description
The proposed Einstein Telescope high-frequency interferometers (ET-HF) in their nominal configuration are limited by coating Brownian thermal noise (CBTN) and quantum shot noise. Achieving the target sensitivity requires up to 3 MW of laser power with advanced optical coatings. At these power levels, thermo-elastic and thermo-optic effects induce wavefront distortions, causing transverse mode mismatch, increased optical loss, and degraded squeezing performance. Parametric instabilities (PI) and CBTN impose additional critical limits.
We present ET-OPT, a 10 m coupled-cavity at UCLouvain, currently being developed to study advanced optical techniques and optical mode control at power densities exceeding that of ET-HF.
In this talk, we will introduce the designs for ET-OPT. This will include the optical mode control strategy, first results analyzing parametric instability suppression, first results on the vacuum envelope and latest results on the generation of the high order optical modes.
Our work will facilitate current detectors to reach the high-power levels demanded in O5. Additionally, this will unlock new techniques to facilitate the use of high order optical modes, reducing CBTN impact, and increasing detectable BNS events in ET at redshift ~10 by a factor of three.