Observation of enhanced optical spring damping in a macroscopic mechanical resonator and application for parametric instability control in advanced gravitational-wave detectors
We show that optical spring damping in an optomechanical resonator can be enhanced by injecting a phase delay in the laser frequency-locking servo to rotate the real and imaginary components of the optical spring constant. This enhances damping at the expense of optical rigidity. We demonstrate enhanced parametric damping which reduces the Q factor of a 0.1-kg-scale resonator from 1.3×10^5 to 6.5×10^3. By using this technique adequate optical spring damping can be obtained to damp parametric instability predicted for advanced laser interferometer gravitational-wave detectors.
© 2008 The American Physical Society. (Received 22 December 2006; published 16 January 2008) This is a project of the Australian Consortium for Gravitational Astronomy, supported by the Australian Research Council and the Western Australian Government OSI. We thank the LSC Gingin Advisory Committee for assistance and support. The LIGO Observatories were constructed by Caltech and MIT with NSF funding under Grant No. PHY-9210038. The LIGO Laboratory operates under cooperative agreement No. PHY-0107417. This paper has been assigned LIGO Document No. LIGO-P060061-00-Z.
Published - SCHEpra08.pdf