Experimental demonstration of a suspended dual recycling interferometer for gravitational wave detection

The advanced scheme of "signal recycling" is to be used in the British-Germ an GEO 600 project, in addition to "power recycling" (which has become stan dard for all laser-interferometer gravitational wave detector projects). Th is combination, "dual recycling," has been demonstrated for the first time on a fully suspended interferometer, the Garching prototype with 30 m arm l ength. Signal enhancement and power buildup were as predicted; operation wa s reliable, and a significant contrast enhancement was observed. A control system that can be extended to full scale gravitational wave detectors was employed.