Towards Ultrastable Amorphous Coatings for LIGO

LIGO 超稳定非晶涂层的研究

• 批准号: 1710957
• 负责人: Carmen Menoni
• 金额: $ 30万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710957&HistoricalAwards=false
• 关键词: Towards; Ultrastable; Amorphous; Coatings; LIGO

The first detection of gravitational waves from the collision of two massive black holes by the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors in Livingston, Louisiana, and Hanford, Washington in 2015 not only confirmed Einstein's predictions of the existence of gravitational waves but also ratified years of efforts in the development of gravitational wave detectors (GWD). Gravitational wave detectors are interferometers in which an intense laser beam bounces between two sets of mirrors in orthogonal arms. Gravitational waves cause differences in the path length of the laser beam between the two interferometer arms, giving rise to a distinct interference pattern that when analyzed identifies the event that created them. The detection sensitivity of GWD is determined by various noise sources, among which, thermal noise of the coatings in the mirrors of the interferometer is a main component. Thermal noise in the high reflectance amorphous oxide coatings in the interferometer's mirrors causes path length differences that can mask the signals from gravitational waves. To increase the sensitivity of present GWD and meet the demands of future GWD, a concerted effort to understand and control the mechanisms that give rise to thermal noise in amorphous oxide coatings is imperative. This work will form part of that effort. This award supports research aimed at demonstrating amorphous oxide coatings with significantly reduced thermal noise and superior optical properties that will enable an approximate 10x increase in sensitivity of state-of-the-art GWD. The research effort has two specific aims: 1) to realize amorphous metal oxide thin films by ion beam sputtering with reduced thermal noise through a systematic parametric study of the deposition conditions used to grow single films; and 2) to engineer multilayer dielectric coatings using these materials with reduced mechanical loss compared to state-of-the-art. A synergistic characterization effort will support the materials' growth. In particular the CSU researchers will collaborate with Caltech researchers to assess mechanical loss in single and multilayer dielectric coatings. This research will support the LIGO program in different ways. Through fundamental studies in amorphous oxides it will enable investigations of the physical mechanisms that come into play in affecting thermal noise. It will also offer the opportunity to seek for new coating designs that will increase sensitivity of advanced LIGO and of the next generation GWD. Synergistic collaborations with the LIGO Scientific Collaboration (LSC) Coatings Group are planned to congruently advance the fundamental material science and coatings engineering efforts.

2015年，位于路易斯安那州利文斯顿和华盛顿汉福德的双激光干涉引力波天文台（LIGO）探测器首次探测到两个大质量黑洞碰撞产生的引力波，不仅证实了爱因斯坦关于引力波存在的预测，而且还批准了多年来在引力波探测器（GWD）开发方面的努力。 引力波探测器是一种干涉仪，其中强激光束在两组正交臂的反射镜之间反射。 引力波会导致两个干涉仪臂之间激光束的路径长度不同，从而产生一个独特的干涉图案，当分析时，可以识别产生它们的事件。GWD的探测灵敏度取决于各种噪声源，其中干涉仪反射镜涂层的热噪声是主要的噪声源。在干涉仪反射镜的高反射率非晶氧化物涂层中的热噪声会导致路径长度的差异，从而掩盖引力波的信号。为了提高目前GWD的灵敏度和满足未来GWD的需求，必须共同努力来理解和控制非晶氧化物涂层中引起热噪声的机制。这项工作将是这一努力的一部分。该奖项支持旨在展示非晶氧化物涂层的研究，该涂层具有显著降低的热噪声和上级光学特性，将使最先进的GWD的灵敏度提高约10倍。该研究工作有两个具体目标：1）通过对用于生长单层膜的沉积条件进行系统的参数研究，通过离子束溅射实现具有降低的热噪声的非晶金属氧化物薄膜;以及2）使用这些材料设计多层介电涂层，与现有技术相比具有降低的机械损耗。协同表征工作将支持材料的生长。特别是，CSU的研究人员将与加州理工学院的研究人员合作，评估单层和多层介电涂层的机械损耗。这项研究将以不同的方式支持LIGO计划。通过对无定形氧化物的基础研究，它将使人们能够研究影响热噪声的物理机制。它还将提供寻找新涂层设计的机会，以提高先进LIGO和下一代GWD的灵敏度。与LIGO科学合作（LSC）涂料集团的协同合作计划一致推进基础材料科学和涂料工程的努力。

项目成果

Investigation of effects of assisted ion bombardment on mechanical loss of sputtered tantala thin films for gravitational wave interferometers

辅助离子轰击对引力波干涉仪溅射氧化钽薄膜机械损耗影响的研究

• DOI: 10.1103/physrevd.100.122004
• 发表时间: 2019
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Yang, Le;Randel, Emmett;Vajente, Gabriele;Ananyeva, Alena;Gustafson, Eric;Markosyan, Ashot;Bassiri, Riccardo;Fejer, Martin M.;Menoni, Carmen S.
• 通讯作者: Menoni, Carmen S.

Modifications of ion beam sputtered tantala thin films by secondary argon and oxygen bombardment

二次氩氧轰击离子束溅射氧化钽薄膜的改性

• DOI: 10.1364/ao.59.00a150
• 发表时间: 2020
• 期刊: Applied Optics
• 影响因子: 1.9
• 作者: Yang, Le;Randel, Emmett;Vajente, Gabriele;Ananyeva, Alena;Gustafson, Eric;Markosyan, Ashot;Bassiri, Riccardo;Fejer, Martin;Menoni, Carmen
• 通讯作者: Menoni, Carmen

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

非晶薄膜体积损失角和剪切损失角的实验测量方法

• DOI: 10.1103/physrevd.101.042004
• 发表时间: 2020
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Vajente, Gabriele;Fazio, Mariana;Yang, Le;Gupta, Anchal;Ananyeva, Alena;Billinsley, Garilynn;Menoni, Carmen S.
• 通讯作者: Menoni, Carmen S.