Optimized multilayer dielectric mirror coatings for gravitational wave interferometers
The limit sensitivity of interferometric gravitational wave antennas is set by the thermal noise in the dielectric mirror coatings. These are currently made of alternating quarter-wavelength high/low index material layers with low mechanical losses. The quarter-wavelength design yields the maximum reflectivity for a fixed number of layers, but not the lowest noise for a prescribed reflectivity. This motivated our recent investigation of optimal thickness configurations, which guarantee the lowest thermal noise for a targeted reflectivity. This communication provides a compact overview of our results, involving nonperiodic genetically-engineered and truncated periodically-layered configurations. Possible implications for the advanced Laser Interferometer Gravitational wave Observatory (LIGO) are discussed.
© 2006 Society of Photo-Optical Instrumentation Engineers (SPIE). This work has been performed within the frame of a MOU with the LIGO Scientific Collaboration (LSC), and has been sponsored in part by the Italian National Institute for Nuclear Physics (INFN, Gruppo V) through the COAT project. The work of J.A. and R.DS. was supported by the National Science Foundation under Grant No. PHY-0107417.
Published - 628608.pdf