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: 2309087
• 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: 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=2309087&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，科学家们在时空中探测到了被称为引力波的涟漪，这种涟漪是由两个黑洞合并产生的，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。计划中的未来升级以提高探测器的灵敏度将需要探测器光学中使用的降低热噪声的镜面涂层。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在理解非晶态氧化物材料的物理方面取得进展，这是该合作项目的核心研究重点。这项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。其目标是创造出满足未来LIGO探测器所需标准的镜面涂层。该团队将继续通过他们的多学科活动和外联活动培训下一代STEM研究人员和专业人员。未来计划中的LIGO升级将寻求安装具有进一步改进的涂层的镜子，特别是具有较低的布朗热噪声(BTN)，这是限制探测器灵敏度的关键噪声源。潜在的A-Sharp升级的基准设计要求涂层的热噪声比高级LIGO+(A+)级别降低至少两倍。斯坦福-佛罗里达项目和涂料研究中心(CCR)之间的协同作用使我们在之前的支持下取得了长足的进步。基于X射线散射和原子结构模型的表征，该团队确定了室温机械损耗与边缘和面共享多面体结构基元之间的联系，提出了掺钛GeO2作为一种高折射率、低机械损耗的涂层。随后CCR和LIGO实验室的实验工作支持了这一鉴定，导致这种材料被选为A+镜。根据该奖项进行的研究建立在这些结果的基础上，目标是找到涂层解决方案，将镜面升级和/或A-Sharp系统的热噪声进一步降低两倍。该小组将与开发无定形涂层的沉积小组反复合作，用他们沉积的材料产生的数据来完善原子结构模型，并根据原子结构和建模工作的结果，为这些小组的合成活动的下一步提供指导。虽然我们的主要工作仍将集中在非晶态涂层上，但该小组也将继续通过表征光吸收和开发双折射模型来为晶态AlGaAs涂层做出贡献，并观察到超出预期布朗贡献的多余噪声。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。