Collaborative Research: Cosmic Explorer Optical Design

几十年来，美国在全球观测引力波的努力中发挥了主导作用，先进的LIGO探测器首次探测到双黑洞并合产生的波，2017年获得了诺贝尔物理学奖，此后又有了更多的天体物理学启示。“宇宙探索者”是美国在未来几十年保持领导地位的手段。下一代引力波天文台的宇宙探索者概念试图回答关于我们宇宙的基本问题，例如：黑洞是如何在宇宙时间内形成的？极端物质的物理学是什么？强引力的真正本质是什么？该项目支持激光干涉仪的概念设计，使宇宙探索者引力波探测器能够达到宇宙范围和精确的观测保真度。为该奖项组建的团队拥有数十年的相关经验，并将在先进LIGO的基础上吸取经验教训，利用传统和新颖的概念和技术，产生一个强大的概念光学设计。在生产这种光学设计的过程中，该奖项还将用于发展劳动力，这将是完成宇宙探索者探测器的设计、安装和调试的进一步阶段所必需的。通过让宇宙探索者更加坚定地走上实现的道路，该奖项将确保引力波科学继续激励全国各地的年轻科学家，以实现他们作为未来世界领先研究人员的潜力。宇宙探测器概念的核心是40公里和20公里的激光干涉仪，它们具有前所未有的应变灵敏度，比先进的LIGO高一个数量级。提高的灵敏度主要是由规模的增加提供的，而不是实施尚未证实的技术进步，从而减少了技术风险。尽管如此，尺度的增加本身给宇宙探索者干涉仪的光学设计带来了独特的挑战，例如寄生光学模式的频率间隔减小，由于腔延迟导致的控制带宽限制，以及低频辅助自由度的更严格的噪声要求。此外，随着全新设施的设计，有机会并行开发光学布局和基础设施，最大限度地减少设施限制对仪器性能的影响，从而实现科学。该合同支持的工作将为“宇宙探索者”干涉仪提供一个参数化概念光学设计，通知所有其他探测器子系统的要求，预计从合同开始日期起大约五年内进行概念设计审查。光学设计分为四个主要工作包，每个工作包由四个合作机构之一领导：核心干涉仪，干涉仪传感和控制，激光稳定和锁定获取，以及读出和量子增强。这些工作包中包含的任务将使用一系列分析和数值模拟技术来解决，并将通过宇宙探测器系统团队与更广泛的宇宙探测器概念设计进行协调。该奖项反映了美国国家科学基金会的法定使命，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。

The US has played a leading role in the global effort toward the observation of gravitational waves for several decades, resulting in the Nobel Physics Prize in 2017 for the first detection of waves from a binary black hole merger by the Advanced LIGO detectors, and many more astrophysical revelations since. Cosmic Explorer is the means by which the US will maintain that leadership in the decades to come. The Cosmic Explorer concept for a next-generation gravitational wave observatory seeks to answer fundamental questions about our universe such as: How did black holes form throughout cosmic time? What is the physics of extreme matter? What is the true nature of strong gravity? This project supports the conceptual design of the laser interferometers that will enable the Cosmic Explorer gravitational wave detectors to achieve cosmological range and exquisite fidelity in their observations. The team assembled for this award brings to bear decades of relevant experience and will build on the lessons learned from Advanced LIGO, leveraging legacy and novel concepts and technologies to produce a robust conceptual optical design. In the process of producing this optical design, the award will also serve to develop the workforce that will be essential for completing the further stages of design, installation and commissioning of the Cosmic Explorer detectors. By putting Cosmic Explorer more firmly on the path to actualization, this award will ensure that gravitational wave science continues inspiring young scientists across the country to fulfill their potential as the world-leading researchers of the future.At the heart of the Cosmic Explorer concept are 40-km and 20-km laser interferometers operating with unprecedented strain sensitivity, an order of magnitude greater than that of Advanced LIGO. The improved sensitivity is primarily afforded by the increase in scale, as opposed to the implementation of as-yet unverified technological advancements, thereby reducing technical risk. Nonetheless, the increase in scale itself presents unique challenges for the optical design of the Cosmic Explorer interferometers, such as decreased frequency spacing of parasitic optical modes, control band-width limitations due to the cavity delay, and tighter noise requirements for auxiliary degrees of freedom at low frequencies. Moreover, with the design of an entirely new facility comes the opportunity to develop the optical layout and the infrastructure in parallel, minimizing facility constraints impact on instrument performance, and therefore the achievable science. The work supported by this award will produce a parametric conceptual optical design for the Cosmic Explorer interferometers, informing all other detector subsystem requirements, ahead of a conceptual design review anticipated to take place roughly five years from the award start date. The optical design has been divided into four main work-packages, each led by one of the four collaborating institutions: Core Interferometer, Interferometer Sensing and Control, Laser Stabilization and Lock Acquisition, and Readout and Quantum Enhancement. The tasks contained within these work packages will be addressed using a range of analytical and numerical simulation techniques and will be coordinated with the broader Cosmic Explorer conceptual design through the Cosmic Explorer Systems Team.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.