Jena 2013 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 4: Gravitationswellen II

GR 4.5: Talk

Tuesday, February 26, 2013, 15:00–15:15, HS 6

Thermal noise in grating reflectors — •Daniel Heinert¹, Stefanie Kroker², Daniel Friedrich³, Stefan Hild⁴, Iain Martin⁴, Ronny Nawrodt¹, Paul Seidel¹, Andreas Tünnermann², Sergey Vyatchanin⁵, and Kazuhiro Yamamoto³ — ¹Institut für Festkörperphysik, FSU Jena, 07743 Jena — ²Institut für Angewandte Physik, FSU Jena, 07745 Jena — ³Institute for Cosmic Ray Research, The University of Tokyo, Kashiwa, Chiba 277-8582, Japan — ⁴SUPA, School of Physics and Astronomy, Institute for Gravitational Research, Glasgow University, Glasgow G12 8QQ, United Kingdom — ⁵Faculty of Physics, Moscow State University, Moscow 119991, Russia

The interferometric detection of gravitational waves is crucially limited by the thermal noise of the detector's optical components. Past investigations have identified the high reflective coating layers to show a high mechanical loss. Due to the fluctuation-dissipation theorem they form the dominating noise source in a detector.

A promising alternative to the use of Bragg mirrors can be found in grating reflectors. Such gratings can be designed to exhibit high reflectivities at a specific design wavelength. These structures significantly reduce or even avoid the use of lossy coating materials and thus are expected to show a decreased amount of thermal noise.

In our contribution we present the noise analysis of grating reflectors. We further apply our theory to a 3rd generation gravitational wave detector. Finally, the noise benefit for the use of a grating reflector compared to a conventional layer stack is estimated.

This work is supported by the DFG under contract SFB TR 7.