Low-frequency losses in silica glass at low temperature

Travasso, F.; Bosi, L.; Dari, A.; Gammaitoni, L.; Vocca, H.; Marchesoni, F.

doi:10.1016/j.msea.2008.09.097

Cited by 6 publications

(7 citation statements)

References 35 publications

(44 reference statements)

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“…As mentioned earlier the measured mechanical loss of a sample can be considered to have components associated with both the surface and bulk of a samples with the intrinsic bulk loss potentially being as low as 4 × 10 −10 at 100 Hz [51]. However investigation of the acoustic absorption of amorphous silica at low temperatures [95][96][97][98][99][100] reveals an issue that makes fused silica unsuited for cryogenic use (see Fig. 5b).…”

Section: Fused Silicamentioning

confidence: 98%

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Challenges in thermal noise for 3rd generation of gravitational wave detectors

et al. 2010

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Various noise sources limit the sensitivity of current interferometric gravitational wave detectors, including seismic noise, thermal noise of the optical components and suspension elements and photon shot noise. Plans are in place for a suite of hardware upgrades which should increase the sensitivity of these detectors by reducing the various noise sources. With these designs for 2nd generation detectors mature, techniques for further improvement of detector sensitivity by a factor of approximately 10 are under study. A particular challenge is the reduction of the thermal noise associated with the interferometer mirrors and their suspensions. We review the current status of research on thermal noise in interferometric gravitational wave detectors. Aspects of possible techniques for use in future '3rd generation detectors' such as cryogenics and diffractive optics are discussed

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Section: Fused Silicamentioning

confidence: 98%

“…Studies show that a large broad mechanical loss peak exists, centered around 40 K, associated with a double well potential associated with the Si-O-Si bonds in the amorphous structure [97,101]. This limits the mechanical loss in this region to the order of 10 −3 [98].…”

Section: Fused Silicamentioning

confidence: 99%

Challenges in thermal noise for 3rd generation of gravitational wave detectors

et al. 2010

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“…However, all previous work 10, [22][23][24]26,27 separate the 2D distribution over the barrier height and asymmetry into the product of 1D distributions:…”

Section: A Tls Modelmentioning

confidence: 99%

“…Throughout the history of the TLS model, the dependence on V and ∆ is assumed to be uncorrelated. 6,9,10,[24][25][26][27] Even though many authors have debated about the form of the TLS distribution [28][29][30][31][32] , the vast majority treat the distributions over V and ∆ separately. As we show in this paper, this assumption is contradictory to the definition of a TLS and does not match the distribution obtained in computational simulations.…”

Section: Introductionmentioning

confidence: 99%

Origin of the second peak in the mechanical loss function of amorphous silica

et al. 2017

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The thermal noise in amorphous oxides is the limiting factor for gravitational wave detectors and other high-precision optical devices. Through the fluctuation-dissipation theorem, the thermal noise is directly connected to the internal friction (Q −1 ). Computational calculations of Q −1 that use a two-level system (TLS) model have previously been performed for several coating materials, facilitating the search for coatings with lower thermal noise. However, they are based on a historical approximation made within the TLS model that treats the TLS distribution as uncorrelated, which has limited the predictive power of the model. In this paper, we demonstrate that this approximation limits the physical description of amorphous oxides using the TLS model and a fully correlated distribution must be used to calculate high-temperature behavior. Not only does using a correlated distribution improve the theoretical standing of the TLS model, calculations of Q −1 using a fully correlated distribution reproduce and uncover the physical mechanisms of a second peak observed in measurements of ion-beam sputtered (IBS) amorphous silica. We also explore the details of the thermal activation of TLS's, and analyze the atomic transitions that contribute to Q −1 in amorphous silica.

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“…The researchers operating at the Perugia unit (M. Colombini, F. Marchesoni, F. Mattarelli, I. Blacks, L. Gammaitoni, H. Vocca) have provided significant contributions to the understanding and modelling of the dissipation mechanisms in glassy oxides at low temperatures [36], [37]. They also designed and constructed apparatus for the measurement of the angle of loss and Young's modulus of thin films, either at ambient temperature or in cryogenic conditions [ realizing different measuring benches for samples of various types (cantilevers, membranes , and mirrors of reduced size) on a broad range of frequencies, which make possible the separation of the thermoelastic, interfacial and volumetric noise components.…”

Section: Teams and Competencesmentioning

confidence: 99%

The AdCoat project coatings for gravitational antennas of second and third generation

Canepa

2014

2014 IEEE Metrology for Aerospace (MetroAeroSpace)

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A relevant example where systems simultaneously capable of quasi ideal reflectivity and extremely low mechanical dissipation play a critical role, is provided by the test masses used in the gravitational waves detectors interferometers. Thermal noise generated by dissipation in the test-masses is the dominating factor in a frequency band, between 50 Hz and a few hundreds Hz, where a high relative sensitivity of the instrument meets a high astrophysical interest. The choice of interferential mirrors (e.g. λ 4 Ta2O5-SiO2 multilayers) negatively impacts on thermal noise as the mechanical losses in the coating are relatively large. Only a substantial reduction of the thermal noise of the mirrors will allow GWDs to reach and possibly exceed the limit represented by the quantum noise. This contribution aims at illustrating AdCoat a nation-wide research program recently launched by INFN, which attempts to gather all groups working in Italy on the reduction of thermal noise in coatings for gravitational antennas of second and third generation.

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Low-frequency losses in silica glass at low temperature

Cited by 6 publications

References 35 publications

Challenges in thermal noise for 3rd generation of gravitational wave detectors

Challenges in thermal noise for 3rd generation of gravitational wave detectors

Origin of the second peak in the mechanical loss function of amorphous silica

The AdCoat project coatings for gravitational antennas of second and third generation

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