Studies of materials for use in future interferometric gravitational wave detectors
Studies of materials for use in future interferometric gravitational wave detectors
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研究用于未来干涉引力波探测器的材料
DOI：
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发表时间：
2009
期刊：
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通讯作者：
I. Martin
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文献类型：
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作者：
I. Martin
广义相对论预言的引力波是时空曲率的波动，它是由质量的非对称加速度引起的。虽然引力波还没有被直接探测到，但对脉冲双星系统内旋速率的测量为引力波的存在提供了强有力的证据，世界范围内正在努力开发更灵敏的探测器。除了测试广义相对论的预测，观测和分析来自天体物理学来源的引力波将为包括黑洞，中子星和超新星在内的广泛现象提供新的见解。
引力波的性质是四重的，因此会在空间产生波动的潮汐应变。长基线引力波探测器的目的是利用激光干涉测量法测量自由质量相对分离的波动，这些探测器被涂上高反射镜，并作为反射镜悬挂在长达4公里的垂直臂末端。目前世界上有几个长基线引力波探测器正在运行，包括美国的三个LIGO探测器，汉诺威附近的英国/德国GEO 600探测器和比萨附近的法国/意大利Virgo探测器。
引力波所产生的应变非常小，只有[~10-[上标22]量级。所得位移的大小使得反射镜及其悬架的热运动形成对检测器灵敏度的重要限制。热噪声的水平与测试质量和反射镜涂层中使用的材料的机械耗散有关。
Gravitational waves, predicted by the theory of General Relativity, are fluctuations in the curvature of space-time which arise from the asymmetric acceleration of mass. While gravitational waves have yet to be detected directly, measurements of the inspiral rate of a binary pulsar system have provided strong evidence for their existence and a world-wide effort to develop more sensitive detectors is ongoing. In addition to testing predictions of General Relativity, observation and analysis of gravitational waves from astrophysical sources will provide new insights into a wide range of phenomena including black holes, neutron stars and supernovae.
Gravitational waves are quadruple in nature, and therefore produce fluctuating tidal strains on space. Long baseline gravitational wave detectors aim to measure this effect using laser interferometry to measure fluctuations in the relative separation of free masses, coated to form highly reflective mirrors and suspended as pendulums at the ends of perpindicular arms up to 4 km in length. There are currently several long baseline gravitational wave detectors in operation around the world, including the three LIGO detectors in the US, the UK/German GEO600 detector near Hannover and the French/Italian Virgo detector near Pisa.
The strain expected from gravitational waves is very small, of order [~10-[superscript 22. The magnitude of the resultant displacement is such that the thermal motion of the mirrors and their suspensions forms an important limit to detector sensitivity. The level of thermal noise is related to the mechanical dissipation of the materials used in the test mass and the mirror coatings.