Jena 2013 – scientific programme
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GR: Fachverband Gravitation und Relativitätstheorie
GR 4: Gravitationswellen II
GR 4.2: Talk
Tuesday, February 26, 2013, 14:15–14:30, HS 6
Optical properties of silicon — •Julius Komma1, Gerd Hofmann1, Christian Schwarz1, Daniel Heinert1, Jessica Steinlechner2, Roman Schnabel2, Paul Seidel1, and Ronny Nawrodt1 — 1Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Helmholtzweg 5, D-07743 Jena, Germany — 2Institut für Gravitationsphysik, Universität Hannover, Callinstraße 38, D-30167 Hannover, Germany
Silicon is the chosen test mass material due to its mechanical and thermal properties for the proposed European gravitational wave detector "Einstein Telescope". For the design of such a detector optical parameters like refractive index, thermo-optic coefficient and absorption play an important role for the calculation of noise and the design of this interferometer. The temperature dependent change of the refractive index causes thermal noise due to thermal fluctuations. Another process induced by the thermo-optic coefficient is thermal lensing.
This contribution gives an overview about the optical properties of silicon. We present the measurement technique of the thermo-optic coefficient and data from 5 to 300 K. Hence estimations of the thermal noise in silicon were done. Furthermore calculations of thermal lensing effects in silicon are shown, especially for the low temperature region in which the Einstein Telescope will be operated.
This work is supported by the German Science Foundation (DFG) under contract SFB Transregio 7.