Nonclassical Interferometry towards Gravitational-Wave Detectors at a Laser Wavelength of 2.1um

2.1um 激光波长下引力波探测器的非经典干涉测量

• 批准号: 388405737
• 负责人: Professor Dr. Roman Schnabel, since 8/2019
• 金额: --
• 依托单位: Institut für Laser-Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/388405737?language=en
• 关键词: Nonclassical; Interferometry; towards; Gravitational; Wave

The recent direct observation of gravitational waves from a binary black-hole merger has marked the beginning of gravitational-wave astronomy. To enable a continuous stream of detections with a high signal-to-noise ratio, upcoming generations of gravitational-wave detectors, which are based on the principle of laser interferometry, will aim at an increase of strain sensitivity by at least an order of magnitude. Through most of the detection band, the limiting noise sources are given by thermal noise in the mirror coatings and substrates, as well as quantum noise of the laser light field. Future detectors foresee a change to crystalline silicon as mirror material and operation at cryogenic temperatures. This will need to be accompanied by a change in laser wavelength to around 2µm, from the currently used 1µm. At the same time, squeezed states of light have been successfully shown to reduce the quantum noise in gravitational-wave detectors. Combining these two advancements is therefore a major step towards a successful era of gravitational-wave astronomy. So far, laser development at around 2µm has been driven by LIDAR and medical applications, therefore little experience exists with the demanding stability requirements for high-power lasers in gravitational-wave detectors. Furthermore, squeezed light has not been demonstrated at 2µm, and photo detectors with a near-unity quantum efficiency - so as to not destroy the fragile nonclassical correlations in the squeezed field - are not yet available.The project team will develop a complete solution for 2µm laser technology aimed at gravitational-wave detection that is solely based on degenerate parametric down-conversion of the existing highly stable 1064nm laser sources. Within this project, we will develop a squeezed-light source at 2.128µm, demonstrating for the first time that this wavelength is compatible with advanced quantum-noise reduction techniques. In addition, we will show compensation of detection loss by optical parametric amplification, partly removing the need for photo detectors with almost perfect quantum efficiency. The results of this work will thus play a significant role in planning and enabling future gravitational-wave detectors, pushing the boundaries of the observable universe.

最近对双黑洞合并产生的引力波的直接观测标志着引力波天文学的开始。为了实现高信噪比的连续探测流，基于激光干涉测量原理的下一代引力波探测器将致力于将应变灵敏度提高至少一个数量级。在大部分探测波段，限制噪声源是由反射镜涂层和衬底中的热噪声以及激光光场的量子噪声给出的。未来的探测器可以预见到晶体硅作为镜面材料的变化，并且可以在低温下工作。这需要将激光波长从目前使用的1 μ m改变到2 μ m左右。同时，光的压缩态已经被成功地证明可以减少引力波探测器中的量子噪声。因此，结合这两项进展是迈向引力波天文学成功时代的重要一步。到目前为止，激光雷达和医疗应用推动了2 μ m左右激光的发展，因此引力波探测器中高功率激光的苛刻稳定性要求缺乏经验。此外，2微米的压缩光还没有被证明，并且具有接近单位量子效率的光电探测器——这样就不会破坏压缩场中脆弱的非经典相关性——还没有可用。项目团队将开发一个完整的解决方案，用于2 μ m激光技术的引力波探测，该技术完全基于现有高稳定的1064nm激光源的简并参数下转换。在这个项目中，我们将开发一个2.128µm的压缩光源，首次证明这个波长与先进的量子降噪技术兼容。此外，我们将展示通过光学参量放大来补偿检测损失，部分地消除了对具有几乎完美量子效率的光电探测器的需求。因此，这项工作的结果将在规划和实现未来的引力波探测器方面发挥重要作用，推动可观测宇宙的边界。

项目成果

NQontrol: An open-source platform for digital control-loops in quantum-optical experiments.

NQontrol：量子光学实验中数字控制回路的开源平台

• DOI: 10.1063/1.5135873
• 发表时间: 2020
• 期刊: The Review of scientific instruments
• 作者: C. Darsow-Fromm;L. Dekant;S. Grebien;M. Schröder;R. Schnabel;S. Steinlechner
• 通讯作者: S. Steinlechner