DFG/NSF: Novel Low Loss Coatings-Enabling the Third Generation of Gravitational-Wave Detectors

DFG/NSF：新型低损耗涂层——实现第三代引力波探测器

• 批准号: 1758669
• 负责人: Martin Fejer
• 金额: $ 27.17万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-15 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1758669&HistoricalAwards=false
• 关键词: DFG; NSF; Novel; Low; Loss

A century ago, Einstein predicted the existence of gravitational waves (GWs) which are ripples in the curvature of space-time. On 14th September 2015, the (second-generation) detectors of the LIGO project made the first direct GW detection. This was a ground-breaking event for fundamental physics, observing for the first time a binary black hole system merging to form a single black hole, and has opened a new window into the universe allowing us to 'listen' to its gravitational signatures. The project supported by this award will enable sensitivities envisioned for the next generation GW detectors and new discoveries in gravitational astronomy, as well as an improvement of the detection rates for black hole and neutron star mergers. Gravitational waves cause changes in the separation of LIGO's mirrors so small that the thermal vibration of the mirrors and their coatings, so called Brownian thermal noise, will limit the sensitivity of current and future detectors. This project will develop new materials with low thermal noise to be used in future LIGO upgrades. This work is a collaborative effort between Martin Fejer's group at Stanford University and Jessica Steinlechner's group at Hamburg University, with this award supporting the US contribution to the collaboration. Progress in this area will benefit a broader applied research community, since there are applications beyond LIGO for low thermal noise coatings: atomic clocks, quantum information systems, precision interferometry all demand low-loss coatings. The nature of this multidisciplinary effort makes it ideal for training graduate students.Thermal noise in highly-reflective mirror coatings is directly proportional to the coating thickness, the mechanical loss of the materials and the mirror temperature. To significantly reduce coating thermal noise, future GW detectors will be cryogenically operated. The aim of this project is the development of highly-reflective multilayer coatings for future GW detectors, based on studies of coating properties, composition and structure, to meet the challenging requirements on absorption, reflectivity and mechanical loss. While this project mainly targets future cryogenic detectors, thermal noise reduction for detector upgrades operating at room temperature detectors is also part of the proposed research. A key part of this effort is optimizing coating materials which have demonstrated lower levels of mechanical loss, such as amorphous silicon and silicon nitride; and investigate the use of nano-layers, proven to suppress crystallization enabling higher heat treatment temperatures, which can lead to lower optical and mechanical losses. Hamburg will have a unique ability to deposit coatings using a pulsed laser deposition (PLD) system with heated substrates and variable laser pulse durations. Stanford has had a leading role within the LSC in developing experimental methods to characterize the optical and structural properties of the amorphous coating materials. This work will be underpinned by studies of coating properties to understand links between deposition parameters, coating structure, loss and absorption.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.

一个世纪前，爱因斯坦（Einstein）预测，在时空曲率上存在重力波（GWS）。 2015年9月14日，LIGO项目的（第二代）检测器进行了首个直接GW检测。这是一个基本物理学的开创性事件，首次观察二进制黑洞系统以形成一个黑洞，并为宇宙打开了一个新窗口，使我们可以“聆听”其重力签名。该奖项支持的项目将使下一代GW探测器和重力天文学的新发现设想敏感性，并提高黑洞和中子星合并的检测率。引力波会导致Ligo的镜子的分离变化，以至于镜子的热振动及其涂层（所谓的Brownian热噪声）将限制当前和未来探测器的灵敏度。该项目将开发具有低热噪声的新材料，以在将来的Ligo升级中使用。这项工作是斯坦福大学马丁·费耶尔（Martin Fejer）的小组与汉堡大学杰西卡·斯坦利奇（Jessica Steinlechner）小组之间的合作努力，该奖项支持美国对合作的贡献。该领域的进展将使更广泛的应用研究社区受益，因为在Ligo以外的应用中，适用于低热噪声涂层：原子钟，量子信息系统，精确干涉测量法，所有需求都需要低损失涂层。这种多学科工作的性质使其非常适合培训研究生。高度反射镜涂层中的噪声与涂层厚度，材料的机械损失和镜像温度成正比。为了显着减少涂层的热噪声，将未来的GW探测器进行低温操作。该项目的目的是开发基于涂层特性，组成和结构的研究，开发了未来GW检测器的高度反射多层涂层，以满足对吸收，反射率和机械损失的挑战性要求。尽管该项目主要针对未来的低温探测器，但在室温检测器上运行的检测器升级的热噪声也是拟议研究的一部分。这项工作的关键部分是优化涂层材料，这些涂层表现出较低的机械损失，例如无定形硅和氮化硅。并研究纳米层的使用，被证明可以抑制结晶，从而实现较高的热处理温度，从而导致光学和机械损失降低。汉堡将具有使用带有加热底物和可变激光脉冲持续时间的脉冲激光沉积（PLD）系统沉积涂料的独特能力。斯坦福大学在LSC中在开发实验方法中发挥了领导作用，以表征无定形涂层材料的光学和结构特性。这项工作将由对涂料特性的研究为基础，以了解沉积参数，涂料结构，损失和吸收之间的联系。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的评估来获得支持的。

项目成果

Influence of deposition parameters on the optical absorption of amorphous silicon thin films

沉积参数对非晶硅薄膜光吸收的影响

• DOI: 10.1103/physrevresearch.2.033308
• 发表时间: 2020
• 期刊: Physical Review Research
• 影响因子: 4.2
• 作者: Terkowski, Lukas;Martin, Iain W.;Axmann, Daniel;Behrendsen, Malte;Pein, Felix;Bell, Angus;Schnabel, Roman;Bassiri, Riccardo;Fejer, Martin M.;Hough, Jim
• 通讯作者: Hough, Jim