Demonstration of light recycling in a Michelson interferometer with Fabry-Perot cavities

We describe the first experimental demonstration of light recycling of a Michelson interferometer with Fabry-Perot cavities in the arms of the interferometer. Light recycling is a technique for efficiently using the light in long-baseline interferometers, such as those being proposed for the detection of gravitational radiation. An increase in the interferometer circulating power by a factor of 18 is observed, which is in good agreement with the expected gain given the losses in the system. Several phenomena associated with this configuration of coupled optical cavities are discussed.