Thermal noise, suspensions and new materials

Thermal noise is a fundamental noise source in a range of precision measurement systems including interferometric gravitational wave detectors where it is particularly important at frequencies less than 100Hz. To achieve the sensitivity levels desired for the coming generation of Advanced gravitational wave detectors requires careful choices for the materials used in the mirror suspensions, mirror substrate and high reflectivity coatings. This includes the use of monolithic lower stage mirror suspensions of fused silica and doped multilayer mirror coatings. In this talk I will review the main areas of research currently ongoing in order to realise the thermal noise requirements of the Advanced detectors. In addition some of the techniques which will be applicable to future generations of detectors will also be discussed. This will include cryogenic silicon and coating free mirrors.