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

合作研究：斯坦福-佛罗里达计划支持 LIGO 涂层和核心光学器件

• 批准号: 2309086
• 负责人: Martin Fejer
• 金额: $ 148.54万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2309086&HistoricalAwards=false
• 关键词: Collaborative; Research; Stanford; Florida; Program

In 2015, scientists detected ripples in spacetime called gravitational waves, created by two black holes merging, which launched the field of gravitational-wave astronomy. Improvements in the sensitivity in the Advanced LIGO detectors made this revolution possible. Planned future upgrades to improve detector sensitivity will require reduced-thermal-noise mirror coatings that are used in the detector optics. These improvements will continue to impact gravitational-wave astronomy for at least 20 years. A planned upgrade called A-sharp aims to reduce the thermal noise from the mirror coatings by at least half. The challenge of developing lower thermal noise coatings requires progress in the understanding of the physics of amorphous oxide materials, which is the core research focus of this collaborative project. The collaboration brings together experts in both experimental and theoretical aspects of this research at Stanford University and the University of Florida. The goal is to create mirror coatings that meet the necessary standards for use in future LIGO detectors. The team will continue to train the next generation of STEM researchers and professionals through their multidisciplinary activities and outreach activities.Future planned upgrades to LIGO will seek to install mirrors with further improved coatings, in particular with lower Brownian thermal noise (BTN), which is a key noise source limiting detector sensitivity. The baseline design for the potential A-sharp upgrade calls for a coating thermal noise reduced by a factor of at least two with respect to Advanced LIGO + (A+) levels. Synergies between the Stanford-Florida program and the Center for Coatings Research (CCR) have enabled considerable progress under previous support. Having identified, based on characterization via X-ray scattering and atomic structure modeling, the connection between room-temperature mechanical losses and edge- and face-shared polyhedral structural motifs, the team proposed Ti-doped GeO2 as a high refractive-index low-mechanical-loss coating. Subsequent experimental work in the CCR and LIGO Lab supported this identification, leading to the selection of this material for the A+ mirrors. The research conducted under this award builds on these results, with a goal of finding coating solutions with a further factor of two reduction in thermal noise for mirror upgrades and/or an A-sharp system. The group will work iteratively with deposition groups developing amorphous coatings, both refining the atomic structure models with data generated from the materials they deposit, and by providing those groups with guidance for next steps in their synthesis campaigns based on the results from the atomic structure and modeling efforts. While the major portion of our work will remain focused on amorphous coatings, the group will also continue to contribute to crystalline AlGaAs coatings by characterizing optical absorption and developing models for birefringence and observed excess noise above the expected Brownian contribution.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，科学家在时空中探测到了两个黑洞合并产生的称为引力波的涟漪，从而开启了引力波天文学领域。先进 LIGO 探测器灵敏度的提高使这场革命成为可能。计划的未来升级以提高探测器灵敏度将需要在探测器光学器件中使用降低热噪声的反射镜涂层。这些改进将在至少 20 年内继续影响引力波天文学。一项名为 A-sharp 的升级计划旨在将镜面涂层的热噪声降低至少一半。开发低热噪声涂层的挑战需要对非晶氧化物材料物理学的理解取得进展，这是该合作项目的核心研究重点。此次合作汇集了斯坦福大学和佛罗里达大学这项研究的实验和理论方面的专家。目标是创建满足未来 LIGO 探测器使用必要标准的镜面涂层。该团队将继续通过多学科活动和外展活动来培训下一代 STEM 研究人员和专业人员。未来计划的 LIGO 升级将寻求安装具有进一步改进涂层的镜子，特别是具有较低布朗热噪声 (BTN) 的反射镜，这是限制探测器灵敏度的关键噪声源。潜在的 A-sharp 升级的基线设计要求涂层热噪声相对于高级 LIGO + (A+) 水平至少降低两倍。斯坦福-佛罗里达项目与涂料研究中心 (CCR) 之间的协同作用在之前的支持下取得了相当大的进展。基于 X 射线散射和原子结构建模的表征，确定了室温机械损耗与边和面共享的多面体结构图案之间的联系，该团队提出掺钛 GeO2 作为一种高折射率低折射率材料。机械损失涂层。 CCR 和 LIGO 实验室的后续实验工作支持了这一鉴定，最终选择了这种材料用于 A+ 反射镜。该奖项下进行的研究建立在这些成果的基础上，目标是寻找涂层解决方案，将热噪声进一步降低两倍，以用于镜面升级和/或 A 型锐系统。该小组将与开发非晶涂层的沉积小组反复合作，利用他们沉积的材料生成的数据完善原子结构模型，并根据原子结构和结果为这些小组提供合成活动下一步的指导。建模工作。虽然我们工作的主要部分仍将集中在非晶涂层上，但该小组还将通过表征光学吸收和开发双折射模型以及观察到的超出预期布朗贡献的过量噪声，继续为结晶 AlGaAs 涂层做出贡献。该奖项反映了 NSF 的法定使命通过使用基金会的智力优点和更广泛的影响审查标准进行评估，并被认为值得支持。