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Structure and morphology of low mechanical loss TiO₂-doped Ta₂O₅

Fazio, Mariana A. and Vajente, Gabriele and Ananyeva, Alena and Markosyan, Ashot and Bassiri, Riccardo and Fejer, Martin M. and Menoni, Carmen S. (2020) Structure and morphology of low mechanical loss TiO₂-doped Ta₂O₅. Optical Materials Express, 10 (7). pp. 1687-1703. ISSN 2159-3930. doi:10.1364/ome.395503.

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The exceptional stability required from high finesse optical cavities and high precision interferometers is fundamentally limited by Brownian motion noise in the interference coatings of the cavity mirrors. In amorphous oxide coatings these thermally driven fluctuations are dominant in the high index layer compared to those in the low index SiO₂ layer in the stack. We present a systematic study of the evolution of the structural and optical properties of ion beam sputtered TiO₂-doped Ta₂O₅ films with annealing temperature. We show that low mechanical loss in TiO₂-doped Ta₂O₅ with a Ti cation ratio = 0.27 is associated with a material that consists of a homogeneous titanium-tantalum-oxygen mixture containing a low density of nanometer sized Ar-filled voids. When the Ti cation ratio is 0.53, phase separation occurs leading to increased mechanical loss. These results suggest that amorphous mixed oxides with low mechanical loss could be identified by considering the thermodynamics of ternary phase formation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Vajente, Gabriele0000-0002-7656-6882
Fejer, Martin M.0000-0002-5512-1905
Menoni, Carmen S.0000-0001-9185-2572
Additional Information:© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. Received 16 Apr 2020; revised 11 Jun 2020; accepted 11 Jun 2020; published 26 Jun 2020. Funding: National Science Foundation Moore Foundation Center for Coatings Research (1710957). The authors declare no conflicts of interest.
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Issue or Number:7
Record Number:CaltechAUTHORS:20200730-111034167
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Official Citation:Mariana A. Fazio, Gabriele Vajente, Alena Ananyeva, Ashot Markosyan, Riccardo Bassiri, Martin M. Fejer, and Carmen S. Menoni, "Structure and morphology of low mechanical loss TiO2-doped Ta2O5," Opt. Mater. Express 10, 1687-1703 (2020)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104655
Deposited By: Tony Diaz
Deposited On:30 Jul 2020 18:24
Last Modified:16 Nov 2021 18:33

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