Collaborative Research: Stanford-Florida program in Support of LIGO on Coatings and Core Optics

合作研究：斯坦福大学-佛罗里达州支持 LIGO 涂层和核心光学器件的项目

• 批准号: 2011776
• 负责人: Hai-Ping Cheng
• 金额: $ 24万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2011776&HistoricalAwards=false
• 关键词: Collaborative; Research; Stanford; Florida; program

This award supports research in relativity and relativistic astrophysics and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. The detection of gravitational waves from coalescing black holes in 2015 launched the field of gravitational wave astronomy. Gravitational-wave detectors with a two-fold increase in sensitivity over Advanced LIGO would yield 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. All future detector upgrades and concepts rely on the development of new mirror coating materials to reduce thermal noise, which is the core research focus this collaborative project between Martin Fejer's group at Stanford University and Hai-Ping Cheng's group at the University of Florida. Reducing this noise source requires reducing the mechanical loss in the mirror coatings on the test masses. The goal of this project is to develop mirror coatings consistent with the mechanical and optical requirements for implementation in future generations of LIGO. Meeting this goal for room temperature detectors requires a solution of a longstanding problem in the physics of amorphous materials: understanding the nature of and finding means to reduce the low-energy excitations in amorphous metal oxides. On a longer time-scale, the proposed 3G detectors' cryogenic operation broadens the possible choice of low-noise mirror materials to include amorphous or crystalline semiconductors.The mid-band sensitivity of the Advanced LIGO detectors is limited by thermal noise resulting from mechanical loss in the mirror coatings, and future upgrades including Advanced LIGO Plus will seek to reduce this source of noise by a factor of two or more. The Stanford-Florida partnership, alongside collaborators in the LSC Center for Coatings Research (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, based on electron and x-ray scattering atomic structure data, will serve as a paradigm informing the development of high-refractive-index amorphous coatings with lower elastic loss. Atomic modeling of coating elastic loss combined with simulations of the coating deposition process will provide guidance for the selection of candidate materials, assist in interpretation of experimental structure data, and will ultimately assist in the design of synthesis experiments. Another long-standing effort at Stanford has been measurements of the absorption of low-optical-loss materials at the sub-ppm/cm level, dating back to the down select between silica and sapphire for initial LIGO test masses. The groups will continue to use the interferometric tool developed for those studies to characterize cryogenic losses in single-crystal silicon samples to evaluate their suitability for implementation in the Voyager technology demonstrator and future cryogenic detectors.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.

该奖项支持相对论和相对论天体物理学的研究，并介绍了NSF“宇宙上的Windows”的优先领域。 2015年，与黑洞结合的引力波的检测引发了引力波天文学领域。与晚期ligo相比，灵敏度提高两倍的重力波检测器将使黑洞合并的检测率增加数量级，并且能够检测到二进制中子星（例如二进制中子星）等昏昏欲睡的物体，从而大大提高了它们的多时间天文学的价值。所有未来的探测器升级和概念都依赖于新镜涂料材料的开发来减少热噪声，这是斯坦福大学马丁·费耶尔（Martin Fejer）小组与佛罗里达大学Hai-ping Cheng小组之间的合作项目的核心研究重点。减少此噪声源需要减少测试质量镜涂层的机械损失。该项目的目的是开发镜像涂层，符合将后代Ligo实施的机械和光学要求一致的镜像。实现此目标的室温探测器需要解决无定形材料物理学长期问题的解决方案：了解减少无定形金属氧化物中低能量激发的性质和查找手段。在更长的时间尺度上，提出的3G检测器的低温操作扩大了低噪声镜像材料的可能选择，包括无定形或晶体半导体。先进的Ligo探测器的中频段灵敏度受热噪声的限制，受镜像中的机械损失以及未来的LIGO损失而造成的噪声将降低噪声或两次噪声。斯坦福 - 弗洛里达的合作伙伴关系以及LSC涂料研究中心（CCR）的合作者还确定了与室温与低温机械损失相关的不同结构图案，这导致了除其他硅除外的最低氧化物氧化物的合成，从而导致了最低的氧化物胶片。展望未来，该结构指南基于电子和X射线散射原子结构数据，将作为一个范式，告知较低弹性损失的高反向折射率无定形涂层的发展。涂层弹性损失的原子建模与涂层沉积过程的模拟相结合，将为选择候选材料的选择提供指导，有助于解释实验结构数据，并最终有助于设计合成实验。斯坦福大学的另一项长期努力是测量在子ppm/cm水平上吸收低光损失材料的方法，可追溯到二氧化硅和蓝宝石之间的下降选择，用于初始的Ligo测试质量。这些小组将继续使用为这些研究开发的干涉工具来表征单晶硅样品中的低温损失，以评估其在Voyager技术演示者和未来低温探测器中的适用性。这奖反映了NSF的立法任务，并被认为是通过使用基金会的智力评估和广泛的评估来评估的，并且值得通过评估来进行评估。

项目成果

Annealing‐Induced Changes in the Atomic Structure of Amorphous Silica, Germania, and Tantala Using Accelerated Molecular Dynamics

退火——利用加速分子动力学引起无定形二氧化硅、二氧化锗和钽原子结构的变化

• DOI: 10.1002/pssb.202000519
• 发表时间: 2021
• 期刊: physica status solidi (b
• 作者: Prasai, Kiran;Bassiri, Riccardo;Cheng, Hai-Ping;Fejer, Martin M.
• 通讯作者: Fejer, Martin M.

Hidden structure in the medium-range order of amorphous zirconia-tantala films

非晶氧化锆-钽薄膜的中程隐藏结构

• DOI: 10.1103/physrevb.108.054103
• 发表时间: 2023
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Mishkin, Alec;Jiang, Jun;Zhang, Rui;Cheng, Hai-Ping;Prasai, Kiran;Bassiri, Riccardo;Fejer, Martin
• 通讯作者: Fejer, Martin

Amorphous Zirconia-doped Tantala modeling and simulations using explicit multi-element spectral neighbor analysis machine learning potentials (EME-SNAP)

使用显式多元素光谱邻域分析机器学习潜力 (EME-SNAP) 对非晶氧化锆掺杂 Tantala 进行建模和模拟

• DOI: 10.1103/physrevmaterials.7.045602
• 发表时间: 2023
• 期刊: Physical Review Materials
• 影响因子: 3.4
• 作者: Jiang, Jun;Li, Xiang-Guo;Mishkin, Alec S.;Zhang, Rui;Bassiri, Riccardo;Fry, James N.;Fejer, Martin M.;Cheng, Hai-Ping
• 通讯作者: Cheng, Hai-Ping