TUESDAY, August 18

LIGO Seminar, 1:00 PM - 2:00 PM, SCR 351 W. Bridge
"Anatomy of Brownian thermal noise in the coated mirrors: 3-D consideration," Ting Hong, Caltech.

Abstract:

Brownian thermal noise arising from mechanical losses in dielectric coatings of mirrors is the dominant noise source of Advanced LIGO in its intermediate(and most sensitive) frequency band. This noise is the combined effect of fluctuations in the thicknesses and refractive indices of coating layers (which in turn depends on the local volume fluctuation), as well as fluctuations of the coating-substrate interface. We present formulas for each piece of noise, as well as their cross correlations, in terms of elastic parameters of the coating material. We will also discuss how the multi-layer structure of the coating might be optimized to suppress Brownian noise.