Speaker
Description
The thermal noise of the main optics is a fundamental limit for the sensitivity of present and future GW detectors. To reduce it, the next generation of GW interferometers will use larger mirrors and will be cryogenic. To reach this goal, it is essential to identify suitable materials for substrates and suspensions. That means not only materials with good thermal, mechanical and optical properties but also materials that would allow big size substrates and thin, long, strong fibers. Sapphire is a good candidate already used in the KAGRA experiment but it is hard to produce substrates larger than 20cm, it is hard to machine and to polish and it is very expensive. A very promising alternative candidate is silicon.
The present work will discuss the status of the R&D project on silicon fibers produced by three different methods, the results obtained so far and the hints to improve them. Moreover, it will present the status of the system to characterize silicon bulks in cryogenics before the complete installation of the silicon monolithic suspension.
