Second generation ground-based gravitational wave detectors, scheduled to be operating by the middle of this decade, will be limited in sensitivity over much of their detection range by optical quantum noise. As they will be operating at power levels close to the tolerance of the optical components, significant further improvement in sensitivity will require the use of quantum optical techniques such as the injection of squeezed states. In this paper we briefly review squeezing and plans for its implementation into advanced gravitational wave detectors.
Lossy quantum-optical metrology with squeezed states