Reducing the mirrors coating noise in laser gravitational-wave antennae by means of double mirrors

Recent researches show that the fluctuations of the dielectric mirrors coating thickness can introduce a substantial part of the future laser gravitational-wave antennae total noise budget. These fluctuations are especially large in the high-reflectivity end mirrors of the Fabry–Perot cavities which are being used in the laser gravitational-wave antennae.We show here that the influence of these fluctuations can be substantially decreased by using additional short Fabry–Perot cavities, tuned in antiresonance instead of the end mirrors.