Bulk and shear mechanical loss of titania-doped tantala

Abernathy, M. R.; Harry, G. M.; Newport, J. M.; Fair, H.; Kinley-Hanlon, M.; Hickey, Sam; Jiffar, Isaac; Gretarsson, A. M.; Penn, S.; Bassiri, R.; Gustafson, E. K.; Martin, I. W.; Rowan, S.

doi:10.1016/j.physleta.2017.08.007

Cited by 14 publications

(17 citation statements)

References 38 publications

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“…We show the result of our analysis for a titania-doped tantala film as an example, and discuss how the experimental data favor a model with different bulk and shear loss angle over a simpler model with equal loss angles. The material studied here is comparable to what was considered in [18], and we note that the results we obtain are different from those obtained in the previous work. More on this topic in section III.…”

Section: Introductioncontrasting

confidence: 73%

“…Comparison of bulk and shear loss angles for the as deposited titania-doped tantala, as obtained in this work and as reported in Abernathy et al[18].…”

supporting

confidence: 69%

“…If we assume that the two films have similar properties, the reason for the discrepancy is not understood at the moment of writing. However, we would like to point out some key differences between the measurement reported in Abernathy et al [18] and our results: the samples were suspended with different techniques, which might induce systematic differences; we measured and subtracted the contribution to the loss angle of the uncoated substrate, while it is not clear how that was treated in Abernathy's work; in our work a larger number of resonant mode was probed; in Abernathy's work bulk and shear loss angles are extracted from pairs of Q measurement, assuming no frequency dependency between the two modes in each pair but allowing for a frequency dependency between pairs, while in our work we directly fit a frequency dependent model to the experimental data; finally, in our work we restricted the fit parameters to physically realizable values, while in Abernathy's the bulk loss angle is predicted to have negative values for high frequencies.…”

Section: Loss Angle Analysismentioning

confidence: 88%

“…More details in section III. Analysis of measurements in terms of bulk and shear loss angles were done in the past for films on a cantilever composed of alternating layers of silicon nitride and silica [17], and for a titania-doped tantala film on a disk suspended with a fiber [18]. We show the result of our analysis for a titania-doped tantala film as an example, and discuss how the experimental data favor a model with different bulk and shear loss angle over a simpler model with equal loss angles.…”

Section: Introductionmentioning

confidence: 99%

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Method for the experimental measurement of bulk and shear loss angles in amorphous thin films

et al. 2020

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Brownian thermal noise is a limiting factor for the sensitivity of many high precision metrology applications, among other gravitational-wave detectors. The origin of Brownian noise can be traced down to internal friction in the amorphous materials that are used for the high reflection coatings. To properly characterize the internal friction in an amorphous material, one needs to consider separately the bulk and shear losses. In most of previous works the two loss angles were considered equal, although without any first principle motivation. In this work we present a method that can be used to extract the material bulk and shear loss angles, based on current state-of-the-art coating ring-down measurement systems. We also show that for titania-doped tantala, a material commonly used in gravitational-wave detector coatings, the experimental data strongly favor a model with two different and distinct loss angles, over the simpler case of one single loss angle. arXiv:1911.12277v2 [cond-mat.mtrl-sci]

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Section: Introductioncontrasting

confidence: 73%

“…Comparison of bulk and shear loss angles for the as deposited titania-doped tantala, as obtained in this work and as reported in Abernathy et al[18].…”

supporting

confidence: 69%

Section: Loss Angle Analysismentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Method for the experimental measurement of bulk and shear loss angles in amorphous thin films

et al. 2020

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“…The loss was sharply divided with the loss in the drumhead modes (2,4,7) being about 4× higher than the loss in the radial modes (1,3,6). This pattern of loss bifurcation, which has been observed previously in amorphous coatings [7] (except in that case the radial modes had higher loss), indicated a large difference in the loss from bulk and shear motion. From this observation, we chose to ana-lyze the AlGaAs samples with a bulk and shear decomposition.…”

Section: Methodsmentioning

confidence: 93%

Mechanical ringdown studies of large-area substrate-transferred GaAs/AlGaAs crystalline coatings

et al. 2019

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We investigated elastic loss in GaAs/AlGaAs multilayers to help determine the suitability of these coatings for future gravitational wave detectors. We measured large (≈ 70-mm diameter) substrate-transferred crystalline coating samples with an improved substrate polish and bonding method. The elastic loss, when decomposed into bulk and shear contributions, was shown to arise entirely from the bulk loss, φ Bulk = (5.33 ± 0.03) × 10 −4 , with φ Shear = (0.0 ± 5.2) × 10 −7 . These results predict the coating loss of an 8-mm diameter coating in a 35-mm long cavity with a 250-µm spot size (radius) to be φ coating = (4.78 ± 0.05) × 10 −5 , in agreement with the published result from direct thermal noise measurement of φ coating = (4 ± 4) × 10 −5 . Bonding defects were shown to have little impact on the overall elastic loss.

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