Experimental investigation of a control scheme for a zero-detuning   resonant sideband extraction interferometer for next-generation   gravitational-wave detectors
  Some next-generation gravitational-wave detectors, such as the American Advanced LIGO project and the Japanese LCGT project, plan to use power recycled resonant sideband extraction (RSE) interferometers for their interferometer's optical configuration. A power recycled zero-detuning (PRZD) RSE interferometer, which is the default design for LCGT, has five main length degrees of freedom that need to be controlled in order to operate a gravitational-wave detector. This task is expected to be very challenging because of the complexity of optical configuration. A new control scheme for a PRZD RSE interferometer has been developed and tested with a prototype interferometer. The PRZD RSE interferometer was successfully locked with the control scheme. It is the first experimental demonstration of a PRZD RSE interferometer with suspended test masses. The result serves as an important step for the operation of LCGT. 
Fumiko Kawazoe (1), Mitsuhiro Fukushima (2), Seiji Kawamura (2),   Volker Leonhardt (2), Osamu Miyakawa (3), Tomoko Morioka ...