Ultra-precisely stabilised lasers are the interferometric light sources at the heart of gravitational wave detectors. To achieve ever-higher detection rates for meaningful gravitational wave astronomy, ever-greater detection sensitivity is required. In this talk, I will introduce the principle of interferometric gravitational wave detection, and highlight some of the advanced technologies employed in Advanced LIGO.
Current-generation gravitational wave detectors are already limited by quantum noise of the laser light over wide ranges of their detection band. One sophisticated technique that is already routinely being employed to increase the quantum-limited sensitivity of gravitational wave detectors is the use of non-classical (fixed-quadrature squeezed) light. I will conclude my talk by showing some recent results, as well as options for quantum noise reduction in laser interferometry and the broader field of quantum optics.