Birefringence Measurements on Crystalline Silicon

Abstract

Crystalline silicon has been proposed as a new test mass material in third generation gravitational wave detectors such as the Einstein Telescope (ET). Birefringence can reduce the interferometric contrast and can produce dynamical disturbances in interferometers. In this work we use the method of polarisation-dependent resonance frequency analysis of Fabry-Perot-cavities containing silicon as a birefringent medium. Our measurements show a birefringence of silicon along the (111) axis of the order of $\Delta n\approx 10^{-7}$ at a laser wavelength of 1550nm and room temperature. A model is presented that explains the results of different settings of our measurements as a superposition of elastic strains caused by external stresses in the sample and plastic strains possibly generated during the production process. An application of our theory on the proposed ET test mass geometry suggests no critical effect on birefringence due to elastic strains.

19 pages, 6 figures, 2 tables

References in corpus (2)

• Quantum Metrology for Gravitational Wave Astronomy
• Indication for dominating surface absorption in crystalline silicon test masses at 1550nm

Cited by in corpus (6)

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• Effects of mirror birefringence and its fluctuations to laser interferometric gravitational wave detectors
• Development of a polarimetry method toward in-situ substrate birefringence characterization of ground-based gravitational wave detectors
• In situ substrate birefringence characterization in gravitational wave detectors using a heterodyne polarimetry method