Ultra-precisely stabilised laser systems are the interferometric light sources at the heart of gravitational wave detectors. It takes large scientific and technological efforts on many different instrumental fronts, however, to achieve ever-higher detection rates for meaningful gravitational wave astronomy, which requires ever-increasing detection sensitivity.

In this colloquium talk I will briefly 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 now routinely being employed to increase the quantum-limited high-frequency sensitivity of gravitational wave detectors is the use of non-classical (fixed-quadrature squeezed) light. I will show some results and limitations of this technique, as well as future options for quantum noise reduction in laser interferometry and the broader field of quantum optics. In this context I will also highlight some applications of the high-frequency “squeezing combs” in our lab.