Publications by authors named "Ken Strain"
Small, highly absorbing points are randomly present on the surfaces of the main interferometer optics in Advanced LIGO. The resulting nanometer scale thermo-elastic deformations and substrate lenses from these micron-scale absorbers significantly reduce the sensitivity of the interferometer directly though a reduction in the power-recycling gain and indirect interactions with the feedback control system. We review the expected surface deformation from point absorbers and provide a pedagogical description of the impact on power buildup in second generation gravitational wave detectors (dual-recycled Fabry-Perot Michelson interferometers).
View Article and Find Full Text PDFWe report on the first demonstration of a fully suspended 10 m Fabry-Perot cavity incorporating a waveguide grating as the coupling mirror. The cavity was kept on resonance by reading out the length fluctuations via the Pound-Drever-Hall method and employing feedback to the laser frequency. From the achieved finesse of 790 the grating reflectivity was determined to exceed 99.
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- * Researchers developed a method to measure absorption in the beam splitter of GEO 600 using thermal lensing effects.
- * They found a bulk absorption rate of less than 0.25 ppm/cm for Suprasil 311 SV at 1064 nm, marking it as the lowest reported absorption in fused silica to date.