Jena 2013 – wissenschaftliches Programm

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GR: Fachverband Gravitation und Relativitätstheorie

GR 23: Poster (permanent)

GR 23.4: Poster

Freitag, 1. März 2013, 14:45–14:45, HS 6

Optical absorption measurements of silicon at 1550 nm — •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 a common material for semiconductors and because of many applications in integrated circuits or devices like solar cells object of many investigations. In the last few years it became also - together with sapphire - one of the most interesting materials for the usage as a bulk material for optics in low noise applications like cryogenic gravitational wave detectors. The desired wavelength in such detectors is 1550 nm because of the low absorption. For this wavelength and the intended low temperatures in the region around 20 K there exists no measured data for the optical absorption in silicon.

We present a comparison of different measurement methods. One is based on the deflection of a probe laser beam due to the creation of a thermal lens created by the absorbed light. Another method is the thermal absorption measurement where the temperature rise of a sample of silicon is measured. Advantages, problems and accuracies of this two methods will be discussed.

This work is supported by the German Science Foundation (DFG) under contract SFB Transregio 7.