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，爱因斯坦预言了引力波的存在，引力波是时空曲率中的涟漪。2015年9月14日，LIGO项目的（第二代）探测器进行了首次直接GW探测。这是基础物理学的一个突破性事件，首次观察到一个双黑洞系统合并形成一个单一的黑洞，并打开了一个新的窗口，使我们能够“倾听”它的引力信号。该奖项支持的项目将实现下一代GW探测器的灵敏度和引力天文学的新发现，以及提高黑洞和中子星星合并的探测率。引力波导致LIGO反射镜间距的变化如此之小，以至于反射镜及其涂层的热振动，即所谓的布朗热噪声，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，用于未来的LIGO升级。这项工作是斯坦福大学的Martin费耶尔团队和汉堡大学的Jessica Steinlechner团队的合作成果，该奖项支持美国对合作的贡献。这一领域的进展将使更广泛的应用研究界受益，因为除了LIGO之外，还有许多应用需要低热噪声涂层：原子钟、量子信息系统、精密干涉测量都需要低损耗涂层。高反射镜涂层中的热噪声与涂层厚度、材料的机械损耗和镜面温度成正比。高反射镜涂层的热噪声与涂层厚度、材料的机械损耗和镜面温度成正比。为了显著降低涂层热噪声，未来的GW探测器将在低温下运行。该项目的目的是基于对涂层性能、成分和结构的研究，为未来的GW探测器开发高反射多层涂层，以满足对吸收、反射率和机械损耗的挑战性要求。虽然该项目主要针对未来的低温探测器，但在室温下运行的探测器升级的热噪声降低也是拟议研究的一部分。这项工作的一个关键部分是优化涂层材料，这些材料已被证明具有较低的机械损耗，如非晶硅和氮化硅;并研究纳米层的使用，这些纳米层被证明可以抑制结晶，从而实现更高的热处理温度，这可以降低光学和机械损耗。汉堡将有一个独特的能力，存款涂层使用脉冲激光沉积（PLD）系统与加热基板和可变的激光脉冲持续时间。斯坦福大学在开发实验方法以表征非晶涂层材料的光学和结构特性方面在LSC中发挥了主导作用。这项工作将得到涂层性能研究的支持，以了解沉积参数，涂层结构，损失和吸收之间的联系。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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