Collaborative Research: LSC Center for Coatings Research

合作研究：LSC 涂料研究中心

• 批准号: 1707863
• 负责人: Steven Penn
• 金额: $ 10.77万
• 依托单位: Hobart and William Smith Colleges
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-15 至 2021-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1707863&HistoricalAwards=false
• 关键词: Collaborative; Research; LSC; Center; Coatings

The LIGO Scientific Collaboration (LSC) Center for Coatings Research (CCR), funded by the NSF and with planned co-funding by the Gordon and Betty Moore Foundation, seeks to extend the reach of the next generation of gravitational wave detectors by addressing the dominant noise source limiting their performance, thermal noise in the interferometer mirrors. This noise reduces the number of observable gravitational wave signals from astronomical sources. It arises from thermal excitation of the vibrational modes of the mirrors in the LIGO detector optics. The effect of these excitations is reduced as the mechanical quality factor (Q) of the mirrors is increased. Since the Q of the mirrors is limited by the reflective coatings deposited on their surfaces, lower noise requires development of better coatings. The CCR combines groups from 10 institutions in the US working on computational modeling of amorphous materials, deposition of coatings, and characterization of their atomic structure and macroscopic properties. These components are often performed by three 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 three communities focused on a unified research goal. Coating thermal noise is also a limiting factor in the fields of precision timing, quantum information, low noise interferometry, and precision measurements like the search for deviations in the gravitational inverse-square law. Coatings improving on the state of the art in mechanical and optical properties developed under this program would be applicable to these communities as well. On broader impacts in education, the mixture of undergraduate institutions with elite graduate programs provides research opportunities at all education levels and establishes clear avenues of advancement for students who wish to pursue a career within the physical sciences. In addition, the CCR has a strong commitment to the advancement of women and underrepresented minorities; and will also continue its participants' activities in issues of education and public outreach through all major channels of public and social media.The A+ LIGO detector, planned for 2021, will reduce quantum noise with squeezed light injection, leaving thermal noise dominant in the mid-band of the detector. Reducing this noise source requires reducing the mechanical dissipation in the mirror coatings on the test masses. The goal of this project is to develop mirror coatings consistent with A+ LIGO's mechanical and optical requirements. Meeting this goal requires solution of a longstanding problem in the physics of amorphous materials: the nature and control of the low-energy excitations in amorphous oxides. On a longer time scale, developing mirror coatings for the cryogenic LIGO Voyager detector broadens the possibilities to include amorphous or crystalline semiconductors. The primary research focus is to find conditions under which amorphous metal-oxide coatings can be deposited as "ultrastable glasses", which have a low density of the structural motifs that form two-level systems, the source of elastic dissipation. A second research track seeks methods to stabilize coatings against crystallization during high temperature annealing, another method known to reduce room temperature elastic losses. For the longer term research towards LIGO Voyager applications, the group will investigate non-oxide coatings such as single-crystal semiconductors AlGaAs and AlGaP, which have shown low mechanical loss for small geometries but whose scale up to the size of LIGO optics is challenging; and also amorphous silicon and silicon nitride, which have attractive mechanical properties but whose optical properties must be improved.

LIGO 科学合作 (LSC) 涂层研究中心 (CCR) 由 NSF 资助，并计划由戈登和贝蒂摩尔基金会共同资助，旨在通过解决主要问题来扩大下一代引力波探测器的覆盖范围。限制其性能的噪声源是干涉仪镜中的热噪声。这种噪声减少了来自天文源的可观测引力波信号的数量。它是由 LIGO 探测器光学器件中镜子的振动模式的热激发产生的。随着反射镜机械品质因数 (Q) 的增加，这些激励的影响会减少。由于镜子的 Q 值受到其表面沉积的反射涂层的限制，因此较低的噪声需要开发更好的涂层。 CCR 汇集了来自美国 10 个机构的小组，致力于非晶材料的计算建模、涂层沉积及其原子结构和宏观特性的表征。这些组件通常由三个不同的社区执行，这些社区彼此相对隔离。 CCR 的实力及其加速发现的承诺源于这三个社区围绕统一研究目标的紧密结合。涂层热噪声也是精密计时、量子信息、低噪声干涉测量和精密测量（例如寻找引力平方反比定律偏差）领域的限制因素。根据该计划开发的改善机械和光学性能的最新涂层也适用于这些社区。在对教育的更广泛影响方面，本科院校与精英研究生课程的结合为所有教育级别提供了研究机会，并为希望在物理科学领域从事职业的学生建立了明确的晋升途径。此外，CCR 坚定致力于提高妇女和代表性不足的少数群体的地位；还将通过公共和社交媒体的所有主要渠道继续其参与者在教育和公共宣传问题上的活动。计划于 2021 年推出的 A+ LIGO 探测器将通过压缩光注入来减少量子噪声，从而使热噪声在中期占主导地位- 探测器的波段。 减少这种噪声源需要减少测试质量上镜面涂层的机械耗散。该项目的目标是开发符合 A+ LIGO 机械和光学要求的镜面涂层。实现这一目标需要解决非晶材料物理学中长期存在的问题：非晶氧化物中低能激发的性质和控制。从长远来看，为低温 LIGO Voyager 探测器开发镜面涂层拓宽了包含非晶或晶体半导体的可能性。主要研究重点是寻找非晶态金属氧化物涂层可以沉积为“超稳定玻璃”的条件，这种玻璃具有形成两级系统的低密度结构图案，这是弹性耗散的来源。第二个研究方向寻求在高温退火过程中稳定涂层以防止结晶的方法，这是另一种已知的减少室温弹性损失的方法。对于 LIGO Voyager 应用的长期研究，该小组将研究非氧化物涂层，例如单晶半导体 AlGaAs 和 AlGaP，这些涂层在小几何形状下表现出较低的机械损耗，但其规模扩大到 LIGO 光学器件的尺寸具有挑战性；还有非晶硅和氮化硅，它们具有有吸引力的机械性能，但其光学性能必须改进。

项目成果

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

大面积基底转移 GaAs/AlGaAs 晶体涂层的机械衰荡研究

• DOI: 10.1364/josab.36.000c15
• 发表时间: 2019-02
• 期刊: Journal of the Optical Society of America B
• 作者: Penn, Steven D.;Kinley;MacMillan, Ian A. O.;Heu, Paula;Follman, David;Deutsch, Christoph;Cole, Garrett D.;Harry, Gregory M.
• 通讯作者: Harry, Gregory M.

High Precision Detection of Change in Intermediate Range Order of Amorphous Zirconia-Doped Tantala Thin Films Due to Annealing

高精度检测非晶氧化锆掺杂钽薄膜因退火引起的中程序变化

• DOI: 10.1103/physrevlett.123.045501
• 发表时间: 2019-07
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Prasai, K.;Jiang, J.;Mishkin, A.;Shyam, B.;Angelova, S.;Birney, R.;Drabold, D. A.;Fazio, M.;Gustafson, E. K.;Harry, G.;et al
• 通讯作者: et al

Effect of elevated substrate temperature deposition on the mechanical losses in tantala thin film coatings

高温沉积对氧化钽薄膜涂层机械损失的影响

• DOI: 10.1088/1361-6382/aaad7c
• 发表时间: 2018-04
• 期刊: Classical and Quantum Gravity
• 影响因子: 3.5
• 作者: Vajente, G;Birney, R;Ananyeva, A;Angelova, S;Asselin, R;Baloukas, B;Bassiri, R;Billingsley, G;Fejer, M M;Gibson, D;et al
• 通讯作者: et al