Frequency dependence of thermal noise in gram-scale cantilever flexures

• Main Authors: Nguyen, Thanh T-H (Author), Mow-Lowry, Conor Malcolm (Author), Slagmolen, Bram J. J (Author), Miller, John (Contributor), Mullavey, Adam J. (Author), Altin, Paul A. (Author), Shaddock, Daniel A. (Author), McClelland, David E. (Author), Gossler, Stefan (Author)
• Other Authors: MIT Kavli Institute for Astrophysics and Space Research (Contributor)
• Format: Article
• Language: English
• Published: American Physical Society, 2015-12-16T14:55:06Z.
• Subjects: Article
• Online Access: Get fulltext

We present measurements of the frequency dependence of thermal noise in aluminum and niobium flexures. Our measurements cover the audio-frequency band from 10 Hz to 10 kHz, which is of particular relevance to ground-based interferometric gravitational wave detectors, and span up to an order of magnitude above and below the fundamental flexure resonances. Results from two flexures are well explained by a simple model in which both structural and thermoelastic loss play a role. The ability of such a model to explain this interplay is important for investigations of quantum-radiation-pressure noise and the standard quantum limit. Furthermore, measurements on a third flexure provide evidence that surface damage can affect the frequency dependence of thermal noise in addition to reducing the quality factor, a result which will aid the understanding of how aging effects impact on thermal noise behavior.
Australian Research Council