Birefringence measurements on crystalline silicon

C. Kruger*, D. Heinert, A. Khalaidovski, J. Steinlechner, R. Nawrodt, R. Schnabel, H. Luck

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


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 polarization-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 approximate to 10(-7) at a laser wavelength of 1550 nm 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.
Original languageEnglish
Article number015012
Number of pages17
JournalClassical and Quantum Gravity
Issue number1
Publication statusPublished - 7 Jan 2016
Externally publishedYes


  • crystalline silicon
  • birefringence
  • gravitational wave detection
  • Einstein telescope

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