Thermo-refractive noise in gravitational wave antennae
  Thermodynamical fluctuations of temperature in mirrors of gravitational wave antennae may be transformed into additional noise not only through thermal expansion coefficient but also through temperature dependence of refraction index. The intensity of this noise is comparable with other known noises and must be taken into account in future steps of the antennas. 
V.B.Braginsky, M.L.Gorodetsky and S.P.Vyatchanin