Crystalline silicon is currently being discussed as test-mass material for future generations of gravitational wave detectors that will operate at cryogenic temperatures. We present optical absorption measurements on a large-dimension sample of crystalline silicon at a wavelength of 1550nm at room temperature. The absorption was measured in a monolithic cavity setup using the photo-thermal self-phase modulation technique. The result for the absorption coefficient of this float-zone sample with a specific resistivity of 11kOhm cm was measured to be \alpha_A=(264 +/- 39)ppm/cm.
@article{arxiv.1210.7763,
title = {Optical Absorption Measurements on Crystalline Silicon at 1550nm},
author = {Jessica Steinlechner and Christoph Krüger and Nico Lastzka and Sebastian Steinlechner and Alexander Khalaidovski and Roman Schnabel},
journal= {arXiv preprint arXiv:1210.7763},
year = {2015}
}