Collaborative Research: LSC Center for Coatings Research

合作研究：LSC 涂料研究中心

• 批准号: 2011719
• 负责人: Frances Hellman
• 金额: $ 54.13万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-15 至 2023-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2011719&HistoricalAwards=false
• 关键词: Collaborative; Research; LSC; Center; Coatings

The detections of gravitational waves from coalescing black holes in 2015 launched the field of gravitational wave astronomy. The NSF-funded “A+” upgrade to Advanced LIGO is designed to achieve an order of magnitude increase in detection rate for black hole coalescences, and enable detection of fainter objects like binary neutron stars, greatly increasing their value for multi-messenger astronomy. The A+ upgrade and all 3rd generation detector designs depend on the development of mirrors with low coating thermal noise. The coating thermal noise is reduced, primarily, by lowering the mechanical (elastic) loss of the mirror materials. The core research focus of the LIGO Scientific Collaboration (LSC) Center for Coatings Research (CCR) is the development of mirror coatings with low mechanical and optical losses for use in A+ and 3rd generation detectors. The research mission of the CCR includes: understanding and reducing mechanical loss in amorphous metal-oxides, the most widely-used materials in mirror coatings; and developing and testing crystalline (AlGaAs) coatings, which have demonstrated low losses for small mirrors. On a longer time-scale, the CCR is developing mirrors compatible with the proposed 3G detectors’ cryogenic operation. The residual noise visible in the time-domain gravitational waveforms of black hole mergers first recorded by Advanced LIGO is mostly due to quantum noise of the light and thermal noise due to the mirror coatings. Since that first discovery much progress has been made in reducing quantum noise and the coupling from seismic, scatter and jitter noise, leaving coating thermal noise as the dominant barrier limiting gravitational-wave astronomy in the most sensitive observation band. Reducing this noise source for future generations of detectors requires reducing the mechanical dissipation in the mirror coatings on the test masses, and forms the main goal of the CCR. The CCR combines groups working on computational modeling, coating deposition, and characterization of atomic structure and macroscopic material properties. These components are often performed by four diverse communities that work in relative isolation from each other. The strength of the CCR and its promise of accelerating discoveries arises from close integration of these communities focused on a unified research goal. In its first two years of operation, research in the CCR has identified different structural motifs associated with room-temperature vs cryogenic mechanical losses, which led to synthesis of germania (GeO2) films giving rise to the lowest-loss amorphous oxide film other than silica. Going forward, this structural guide will serve as a paradigm informing the development of high-refractive index amorphous coatings with lower elastic loss. In addition, thermo-optically-optimized AlGaAs crystalline coatings have demonstrated a coating thermal noise well below the requirements for A+, and the CCR has generated a development schedule to scale up these coatings to LIGO mirror sizes and will continue investigations into these materials. Other research paths include: exploring deposition techniques to produce “ultrastable glasses” using amorphous metal-oxides; and stabilizing amorphous coatings against crystallization in order to allow elastic loss reduction via high temperature annealing either with nano-layering or with different doping materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

2015年对合并黑洞引力波的探测开启了引力波天文学领域。美国国家科学基金会资助的“A+”升级到高级LIGO，旨在将黑洞合并的探测率提高一个数量级，并能够探测到双中子星等较暗的物体，大大提高它们在多信使天文学中的价值。A+升级和所有第三代探测器设计都依赖于低涂层热噪声反射镜的发展。降低涂层热噪声主要是通过降低镜面材料的机械（弹性）损耗来实现的。LIGO科学合作（LSC）涂层研究中心（CCR）的核心研究重点是开发用于A+和第三代探测器的低机械和光学损耗的镜面涂层。CCR的研究任务包括：了解和减少非晶态金属氧化物的机械损耗，非晶态金属氧化物是镜面涂层中应用最广泛的材料；开发和测试晶体（AlGaAs）涂层，这种涂层已经证明了小镜子的低损耗。在更长的时间尺度上，CCR正在开发与提议的3G探测器低温操作兼容的反射镜。先进LIGO首次记录的黑洞并合的时域引力波形中可见的残余噪声主要是由于光的量子噪声和反射镜涂层引起的热噪声。自第一次发现以来，在减少量子噪声以及地震、散射和抖动噪声的耦合方面取得了很大进展，使涂层热噪声成为限制引力波天文学在最敏感观测波段的主要障碍。为未来几代探测器减少这种噪声源需要减少测试质量上反射镜涂层的机械耗散，这是CCR的主要目标。CCR结合了计算建模、涂层沉积、原子结构表征和宏观材料特性的研究小组。这些组件通常由四个不同的社区执行，这些社区彼此相对隔离地工作。CCR的力量及其加速发现的承诺源于这些专注于统一研究目标的社区的密切整合。在CCR运行的头两年里，研究已经确定了与室温和低温机械损耗相关的不同结构基序，这导致了锗（GeO2）薄膜的合成，从而产生了除二氧化硅以外损耗最低的非晶态氧化膜。展望未来，该结构指南将为开发具有低弹性损失的高折射率非晶涂层提供范例。此外，热光学优化的AlGaAs晶体涂层已经证明涂层的热噪声远低于a +的要求，CCR已经制定了一个开发计划，将这些涂层扩大到LIGO反射镜的尺寸，并将继续研究这些材料。其他研究途径包括：探索使用非晶金属氧化物生产“超稳定玻璃”的沉积技术；并且稳定非晶涂层，防止结晶，以便通过纳米层或不同掺杂材料的高温退火来降低弹性损失。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Structural tunability and origin of two-level systems in amorphous silicon

非晶硅中两能级系统的结构可调性和起源

• DOI: 10.1103/physrevmaterials.6.045604
• 发表时间: 2022
• 期刊: Physical Review Materials
• 影响因子: 3.4
• 作者: Jacks, H. C.;Molina-Ruiz, M.;Weber, M. H.;Maldonis, J. J.;Voyles, P. M.;Abernathy, M. R.;Metcalf, T. H.;Liu, X.;Hellman, F.
• 通讯作者: Hellman, F.

Comparing amorphous silicon prepared by electron-beam evaporation and sputtering toward eliminating atomic tunneling states

比较通过电子束蒸发和溅射制备的消除原子隧道态的非晶硅

• DOI: 10.1016/j.jallcom.2020.157431
• 发表时间: 2021
• 期刊: Journal of Alloys and Compounds
• 影响因子: 6.2
• 作者: Liu, Xiao;Abernathy, Matthew R.;Metcalf, Thomas H.;Jugdersuren, Battogtokh;Culbertson, James C.;Molina-Ruiz, Manel;Hellman, Frances
• 通讯作者: Hellman, Frances

Hydrogen-Induced Ultralow Optical Absorption and Mechanical Loss in Amorphous Silicon for Gravitational-Wave Detectors

用于引力波探测器的非晶硅中氢致超低光吸收和机械损耗

• DOI: 10.1103/physrevlett.131.256902
• 发表时间: 2023
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Molina-Ruiz, M.;Markosyan, A.;Bassiri, R.;Fejer, M. M.;Abernathy, M.;Metcalf, T. H.;Liu, X.;Vajente, G.;Ananyeva, A.;Hellman, F.
• 通讯作者: Hellman, F.

Strategies to reduce the thermoelastic loss of multimaterial coated finite substrates

减少多材料涂层有限基材热弹性损失的策略

• DOI: 10.1088/1361-6382/acdd49
• 发表时间: 2023
• 期刊: Classical and Quantum Gravity
• 影响因子: 3.5
• 作者: Zhou, R;Molina-Ruiz, M;Hellman, F
• 通讯作者: Hellman, F