Mechanical quality factor of a sapphire fiber at cryogenic temperatures

TL;DR

This study measures a high mechanical quality factor of sapphire fibers at cryogenic temperatures, indicating potential for reducing thermal noise in gravitational wave detectors.

Contribution

It provides the first measurement of a sapphire fiber's mechanical quality factor at cryogenic temperatures relevant for gravitational wave detection.

Findings

Mechanical Q factor of 1.1 x 10^7 at 6 K

Potential for thermal noise reduction in cryogenic mirrors

Supports use of sapphire fibers in gravitational wave detectors

Abstract

A mechanical quality factor of $1.1 \times 10^{7}$ was obtained for the 199 Hz bending vibrational mode in a monocrystalline sapphire fiber at 6 K. Consequently, we confirm that pendulum thermal noise of cryogenic mirrors used for gravitational wave detectors can be reduced by the sapphire fiber suspension.