This book offers a comprehensive and complete description of a new scheme to stabilize the power of a laser on a level needed for high precision metrology experiments. The novel aspect of the scheme is sensing power fluctuations via the radiation pressure driven motion they induce on a micro-oscillator mirror. It is shown that the proposed technique can result in higher signals for power fluctuations than what is achieved by a direct power detection, and also that it enables the generation of a strong bright squeezed beam. The book starts with the basics of power stabilization and an overview on the current state of art. Then, detailed theoretical calculations are performed, and the advantages of the new scheme are highlighted. Finally, a proof-of-principle experiment is described and its results are analyzed in details. The success of the work presented here paves a way for achieving high power stability in future experiments and is of interest for high precision metrology experiments, like gravitational wave detectors, and optomechanical experiments.Nominated as an outstanding PhD thesis by the Gravitational Wave International Committee.