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Amorphous oxides to improve the coatings of future gravitational wave detectors

ORAL

Abstract

Amorphous oxides like tantala and titania-doped-tantala have been used as high index material for high reflectivity coatings in many applications, including the mirrors of current gravitational wave detectors. The sensitivity of those detectors is currently limited by coating Brownian noise, which is related to elastic energy loss in the coatings, as shown by the Fluctuation-Dissipation Theorem. This motivates a wide range search of an alternative amorphous material with lower mechanical loss, that could provide a substitute for the high refractive index currently used, namely titania-doped-tantala.
We characterized the optical and elastic properties of several oxides: yttria, hafnia, niobia, alumina, zirconia, zinc oxide, germania and doped germania. We also measured the mechanical loss at room temperature of all materials. Additionally, we performed several heat cycles and measured the changes induced in the mechanical loss.
We found interesting results for germania and doped germania: they exhibit room-temperature loss angles much lower than all oxides other than silica, making them a promising candidate for the high reflectivity coatings of future gravitational wave detectors.

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Presenters

  • Gabriele Vajente

    California Institute of Technology, LIGO Laboratory, California Institute of Technology, Caltech

Authors

  • Gabriele Vajente

    California Institute of Technology, LIGO Laboratory, California Institute of Technology, Caltech

  • Mariana Fazio

    Colorado State University, Department of Electrical and Computer Engineering, Colorado State University, Department of Electrical and Computer Engineering, Colorado State University Fort Collins

  • Le Yang

    Colorado State University, Department of Chemistry, Colorado State University, Department of Chemistry, Colorado State University Fort Collins

  • Alena Ananyeva

    California Institute of Technology, LIGO Laboratory, California Institute of Technology, Caltech

  • GariLynn Billingsley

    California Institute of Technology, LIGO Laboratory, California Institute of Technology, Caltech

  • Ashot Markosyan

    Stanford University, Department of Applied Physics, Ginzton Laboratory, Stanford University, Edward L. Ginzton Laboratory, Stanford University

  • Riccardo Bassiri

    E. L. Ginzton Laboratory, Stanford University, Stanford University, Department of Applied Physics, Ginzton Laboratory, Stanford University, Edward L. Ginzton Laboratory, Stanford University, E.L. Ginzton Laboratory, Stanford University

  • Martin M. Fejer

    E. L. Ginzton Laboratory, Stanford University, Stanford University, Department of Applied Physics, Ginzton Laboratory, Stanford University, Edward L. Ginzton Laboratory, Stanford University, E.L. Ginzton Laboratory, Stanford University

  • Carmen Susana Menoni

    Colorado State University, Department of Electrical and Computer Engineering, Department of Chemistry, Colorado State University, Department of Electrical and Computer Engineering, Colorado State University Fort Collins