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Q: Fachverband Quantenoptik und Photonik
Q 9: Precision Measurements and Metrology II
Q 9.3: Talk
Monday, March 14, 2022, 17:15–17:30, Q-H11
Investigation of Photoelastic Noise in Einstein Telescope — •Jan Meyer1,2, Stefanie Kroker1,2,3, Mika Gaedtke2,4, and Johannes Dickmann1,2,3 — 1TU Braunschweig, Institut für Halbleiterphysik, Germany — 2LENA Laboratory for Emerging Nanometrology, Braunschweig, Germany — 3Physikalisch-Technische Bundesanstalt, Braunschweig — 4Leibniz Universität Hannover, Hannover, Germany
Since the first direct detection of gravitational waves in 2015, the research in the field of interferometric gravitational wave detectors underwent a decisive progress. The second generation of the Laser Interferometer Gravitational-Wave Observatory (Advanced LIGO) and Advanced VIRGO utilizes pioneering noise reduction techniques like squeezing of light to reach sensitivities of better than 1E-23. The most critical noise sources limiting this precision are driven by thermal fluctuations in the optical components. To ensure that future gravitational wave detectors can reach their best possible sensitivity, all noise sources have to be investigated. In this contribution, we quantify photoelastic fluctuations in solids as a noise source in Einstein Telescope (ET). The local variations of the stress caused by thermal fluctuations lead to fluctuations of the refractive index due to the photoelastic material property. We present calculations of the photoelastic noise in the beam splitter and the input test mass of the ET. We show that the amplitude of the photoelastic noise in the ET low-frequency detector is about four orders of magnitude below the maximum design sensitivity and five orders of magnitude below that of the ET high-frequency detector.