title: Measurement of birefringence of low-loss, high-reflectance coating of m-axis sapphire.
abstract: The birefringence of a low-loss, high-reflectance coating applied to an 8-cm-diameter sapphire crystal grown in the m-axis direction has been mapped. By monitoring the transmission of a high-finesse Fabry-Perot cavity as a function of the polarization of the input light, we find an upper limit for the magnitude of the birefringence of 2.5 x 10(-4) rad and an upper limit in the variation in direction of the birefringence of 10 deg. These values are sufficiently small to allow consideration of m-axis sapphire as a substrate material for the optics of the advanced detector at the Laser Interferometer Gravitational Wave Observatory.
authors: J B
authors: JB
authors: Camp
authors: W
authors: W
authors: Kells
authors: M M
authors: MM
authors: Fejer
authors: E
authors: E
authors: Gustafson