Measurements of mechanical thermal noise and energy dissipation in optical dielectric coatings

Li, Tianjun; Sandoval, Felipe Aguilar; Geitner, Mickaël; Bellon, Ludovic; Cagnoli, G.; Degallaix, J.; Dolique, V.; Flaminio, R.; Forest, Danièle; Granata, M.; Michel, C.; Morgado, N.; Pinard, L.

doi:10.1103/physrevd.89.092004

Cited by 31 publications

(34 citation statements)

References 20 publications

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“…The variation of loss observed from mode to mode is larger than the statistical uncertainty. On the contrary, from other measurements [17], we know that the expected loss of sputtered tantala is constant with frequency: that means other systematic effects related to the presence of coatings have to be considered in order to justify the observed variation of loss. The loss decreases with the increase of annealing temperature until the material becomes polycrystalline above 600…”

Section: Comments and Conclusionmentioning

confidence: 77%

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Internal Friction and Young's Modulus Measurements on SiO2 and Ta2O5 Films Done with an Ultra-High Q Silicon-Wafer Suspension

Balzarini¹,

Degallaix²,

Dolique³

et al. 2015

Archives of Metallurgy and Materials

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In order to study the internal friction of thin films a nodal suspension system called GeNS (Gentle Nodal Suspension) has been developed. The key features of this system are: i) the possibility to use substrates easily available like silicon wafers; ii) extremely low excess losses coming from the suspension system which allows to measure Q factors in excess of 2×10 8 on 3" diameter wafers; iii) reproducibility of measurements within few percent on mechanical losses and 0.01% on resonant frequencies; iv) absence of clamping; v) the capability to operate at cryogenic temperatures. Measurements at cryogenic temperatures on SiO 2 and at room temperature only on Ta 2 O 5 films deposited on silicon are presented.Keywords: Ultra low loss suspensions, Q measurements, optical dielectric coatings, silica, tantala Ta 2 O 5 , thin films Aby umożliwić prowadzenie badań tarcia wewnętrznego (Q −1 ) w cienkich warstwach opracowano węzłowy układ zawieszenia o nazwie GeNS (Gentle Nodal Suspension). Do najważniejszych cech charakterystycznych tego układu zaliczamy: i) możliwość wykorzystania łatwo dostępnych substratów, takich jak wafle krzemowe; ii) bardzo niskie straty nadmiarowe pochodzące z samego układu zawieszenia, co umożliwia pomiar wielkości Q przekraczających wartość 2×10 8 na waflach o średnicy 3"; iii) powtarzalność wyników pomiarów strat mechanicznych w zakresie kilku procent, a częstotliwości rezonansowej w zakresie 0,01%; iv) brak mocowań próbki; v) możliwość prowadzenia pomiarów w temperaturach kriogenicznych. W pracy przedstawiono wyniki pomiarów uzyskanych w temperaturach kriogenicznych dla SiO 2 i przy temperaturze pokojowej dla warstw Ta 2 O 5 osadzonych na krzemie.

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Section: Comments and Conclusionmentioning

confidence: 77%

“…(4)), a tantala Young's modulus of about 110 GPa has been worked out. The difference may be explained by a different choice of deposition parameters between our samples and those of reference [23] from where the tantala Young's modulus used in the calculations and FEA [17] has been taken. Fig.…”

Section: Comments and Conclusionmentioning

confidence: 99%

Internal Friction and Young's Modulus Measurements on SiO2 and Ta2O5 Films Done with an Ultra-High Q Silicon-Wafer Suspension

Balzarini¹,

Degallaix²,

Dolique³

et al. 2015

Archives of Metallurgy and Materials

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“…where φ i,tot is the loss angle of coated disk and φ i,s is the loss angle of the substrate. D i is the so-called dilution factor which can be related to f i,s , f i,tot , m s and m tot [8], that are the frequencies and the mass of the sample before and after the coating deposition, respectively. of doping.…”

mentioning

confidence: 99%

High-Reflection Coatings for Gravitational-Wave Detectors:State of The Art and Future Developments

Amato

Cagnoli

Canepa

et al. 2018

J. Phys.: Conf. Ser.

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Abstract. We report on the optical, mechanical and structural characterization of the sputtered coating materials of Advanced LIGO, Advanced Virgo and KAGRA gravitationalwaves detectors. We present the latest results of our research program aiming at decreasing coating thermal noise through doping, optimization of deposition parameters and postdeposition annealing. Finally, we propose sputtered Si 3N4 as a candidate material for the mirrors of future detectors.

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“…shape, and can be written as a function of the mode frequency and the mass of the sample before and after the coating deposition ( f s_i , f i , m s and m, respectively) [19],…”

Section: Measurementmentioning

confidence: 99%

Progress in the measurement and reduction of thermal noise in optical coatings for gravitational-wave detectors

et al. 2020

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Coating thermal noise is a fundamental limit for precision experiments based on optical and quantum transducers. In this review, after a brief overview of the techniques for coating thermal noise measurements, we present the latest world-wide research activity on low-noise coatings, with a focus on the results obtained at the Laboratoire des Matériaux Avancés. We report new updated values for the Ta 2 O 5 , Ta 2 O 5 -TiO 2 and SiO 2 coatings of the Advanced LIGO, Advanced Virgo and KAGRA detectors, and new results from sputtered Nb 2 O 5 , TiO 2 -Nb 2 O 5 , Ta 2 O 5 -ZrO 2 , MgF 2 , AlF 3 and silicon nitride coatings. Amorphous silicon, crystalline coatings, high-temperature deposition, multi-material coatings and composite layers are also briefly discussed, together with the latest developments of structural analyses and models. The issue of coating thermal noiseThe Laboratoire des Matériaux Avancés (LMA, now a division of the newly created Institut de Physique des 2 Infinis de Lyon) has provided the current high-reflection (HR) and anti-reflective (AR) coatings of the most critical optics of Advanced LIGO [1], Advanced Virgo [2] and KAGRA [3]. In these gravitational-wave (GW) interferometers, large and massive suspended mirrors (typically with ∅ = 35 cm, t = 20 cm, m = 40 kg) form the km-long resonant Fabry-Perot cavities where the astrophysical signals are embedded in the laser beam phase. Their HR coatings are Bragg reflectors of alternate layers of ion-beam-sputtered (IBS) low-and high-refractive index materials, which feature outstanding optical properties [4]. At the same time, these amorphous coatings are the source of coating thermal noise (CTN), which is a severe limitation to the detector sensitivity [1,2].In GW interferometers, thermal noise arises from fluctuations of the mirror surface under the random motion of particles in coatings and substrates [5,6]. Its power spectral density is determined by the amount of internal friction within the mirror materials, via the fluctuationdissipation theorem [7]: the higher the elastic energy loss, the higher the thermal noise level. As the coating loss is usually several orders of magnitude larger than that of the substrate [8,9], CTN is the dominant source of noise in the mirrors.More generally, CTN is a fundamental limit for precision experiments based on optical and quantum transducers, such as opto-mechanical resonators [10], frequency standards [11] and quantum computers [12]. In the last two decades, a considerable research effort has been committed to the measurement and the reduction of CTN.

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Measurements of mechanical thermal noise and energy dissipation in optical dielectric coatings

Cited by 31 publications

References 20 publications

Internal Friction and Young's Modulus Measurements on SiO2 and Ta2O5 Films Done with an Ultra-High Q Silicon-Wafer Suspension

Internal Friction and Young's Modulus Measurements on SiO2 and Ta2O5 Films Done with an Ultra-High Q Silicon-Wafer Suspension

High-Reflection Coatings for Gravitational-Wave Detectors:State of The Art and Future Developments

Progress in the measurement and reduction of thermal noise in optical coatings for gravitational-wave detectors

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