Abstract

Crystalline materials are promising candidates as substrates or high-reflective coatings of mirrors to reduce thermal noises in future laser interferometric gravitational wave detectors. However, birefringence of such materials could degrade detector sensitivity through optical losses and additional phase noise from birefringence fluctuations. This paper analytically estimates the effects of birefringence and its fluctuations in mirror substrates and coatings for gravitational wave detectors, derives alignment conditions for polarization and crystal axes, and gives requirements for birefringence fluctuations in silicon substrates and AlGaAs coatings at 100 Hz.

Abstract

Crystalline materials are promising candidates as substrates or high-reflective coatings of mirrors to reduce thermal noises in future laser interferometric gravitational wave detectors. However, birefringence of such materials could degrade detector sensitivity through optical losses and additional phase noise from birefringence fluctuations. This paper analytically estimates the effects of birefringence and its fluctuations in mirror substrates and coatings for gravitational wave detectors, derives alignment conditions for polarization and crystal axes, and gives requirements for birefringence fluctuations in silicon substrates and AlGaAs coatings at 100 Hz.

Abstract

Crystalline materials are promising candidates as substrates or high-reflective coatings of mirrors to reduce thermal noises in future laser interferometric gravitational wave detectors. However, birefringence of such materials could degrade detector sensitivity through optical losses and additional phase noise from birefringence fluctuations. This paper analytically estimates the effects of birefringence and its fluctuations in mirror substrates and coatings for gravitational wave detectors, derives alignment conditions for polarization and crystal axes, and gives requirements for birefringence fluctuations in silicon substrates and AlGaAs coatings at 100 Hz.

Abstract

Crystalline materials are promising candidates as substrates or high-reflective coatings of mirrors to reduce thermal noises in future laser interferometric gravitational wave detectors. However, birefringence of such materials could degrade detector sensitivity through optical losses and additional phase noise from birefringence fluctuations. This paper analytically estimates the effects of birefringence and its fluctuations in mirror substrates and coatings for gravitational wave detectors, derives alignment conditions for polarization and crystal axes, and gives requirements for birefringence fluctuations in silicon substrates and AlGaAs coatings at 100 Hz.